Which is a compound sentence? a. while my brother takes his dance class, i go to soccer practice

You did not include the rest of the question but with some googling i believe the answer you are looking for is:

A compound sentence is a sentence with more than one subject or predicate so... I painted my bedroom beige, but my sister painted her room blue is  the answer

obama was told in early july 2004 that he was chosen to deliver the address, and he largely wrote the speech himself, with later edits from the kerry presidential campaign.

i've read it so how can i ?