What does 1° mean in orchestral music when put beside a single line of music in a bassoon part that had prevously been playing in 2 parts?

Does it mean:
a) they both play the same thing?
b) only one of them plays the music?
c) something else?

It looks like only Bassoon 1 plays. Bassoon 2 can count the rests and turn the page if necessary!

Thanks!!

I LOL at your 25m swimming badge! Well done!

Its an abbreviation for "Solo" hence the little "o" at the end :-)

More likely "primo", though that is also abbreviate 1mo (not pronounced "one-ee-moe", as a lady conductor and composer I knew said it ).