get an A on the class vs get an A in the class

Some examples from the web:

• No one gets an A-plus in Gerard's class.
• Everyone takes this class to get an A.
• If everyone in the college preparatory class gets an A, then we'll acknowledge his skills.
• Anyone tells me why her heart stopped gets an A in Dr. Cuddy's class.
• The STMs, which enable the Class A on-board system to operate over Class B infrastructure, are subject to the Class B requirements.
• STM: the specific transmission module (STM) allows class A on-board equipment to operate on lines fitted with class B signalling by using the class B data.
• Requirements for Class B systems and for STMs (which enable the Class A On-board system to operate on Class B infrastructure) are the responsibility of the appropriate Member State.
• Class president and the class clown.
• I will... I will get an A in every single class.
• This product belongs to the class of dermocorticoids.
• Tracleer tablets belong to the class of medicines called endothelin receptor antagonists.
• Half the class is failing English.
• - I'm dropping the class.
• Aliskiren belongs to the class of direct renin inhibitors and hydrochlorothiazide to the class of thiazide diuretics.
• The interface between the Class A on-board system and STM's is defined in this TSI. Member States have the responsibility to ensure that Class B systems are managed during their lifetime; in particular any changes to these specifications must not prejudice interoperability.
• For the last time, Mr. Kerwin, I have to get an A on this, because without it, I drop to number two in my class, and if I'm not valedictorian...
• How else am I supposed to get an A in your class, right?
• So you're saying, that all three of us have to get an A in the composing class in order to bring Mr. Kang back?
• The Class A train protection system is ERTMS/ETCS whilst the Class A radio system is GSM-R.
• He never registered for the class.

Some examples from the web:

• So you're saying, that all three of us have to get an A in the composing class in order to bring Mr. Kang back?
• Anyone tells me why her heart stopped gets an A in Dr. Cuddy's class.
• No one gets an A-plus in Gerard's class.
• Everyone takes this class to get an A.
• I will... I will get an A in every single class.
• If everyone in the college preparatory class gets an A, then we'll acknowledge his skills.
• How else am I supposed to get an A in your class, right?
• Class president and the class clown.
• This product belongs to the class of dermocorticoids.
• Tracleer tablets belong to the class of medicines called endothelin receptor antagonists.
• Half the class is failing English.
• - I'm dropping the class.
• Aliskiren belongs to the class of direct renin inhibitors and hydrochlorothiazide to the class of thiazide diuretics.
• The only way to get an A in my class is to have lived in the 20th century.
• The Class A train protection system is ERTMS/ETCS whilst the Class A radio system is GSM-R.
• The STMs, which enable the Class A on-board system to operate over Class B infrastructure, are subject to the Class B requirements.
• He never registered for the class.
• The class is out there, ladies.
• Get out of the class, please.
• Get out of the class, please.