What is this type of note, the accented quarter notes with the black circles on both sides? (the instrument is bells/marimba) am i just playing two notes at the same time?

Although I am not positive, that note looks like a marcato- I'm not very good with music but I am pretty sure you play your instrument noticeably forcefully than other instruments around. The piece probably indicated that it wants you to do it in double sets.

The answer to this question is b.