help...Which sentence uses punctuation correctly?

A.
Since she is determined to become an astronaut my sister is taking extra classes in math and physics.

B.
Since she is determined to become an astronaut my sister is taking extra classes, in math and physics.

C.
My sister, since she is determined to become an astronaut, is taking extra classes in math and physics.

D.
My sister since she is determined to become an astronaut is taking extra classes in math and physics.

Question

help...Which sentence uses punctuation correctly?	
 
 A.
Since she is determined to become an astronaut my sister is taking extra classes in math and physics.
 
 B.
Since she is determined to become an astronaut my sister is taking extra classes, in math and physics.
 
 C.
My sister, since she is determined to become an astronaut, is taking extra classes in math and physics.
 
 D.
My sister since she is determined to become an astronaut is taking extra classes in math and physics.

anonymous · Answer

i think it is c

anonymous · Answer

I thought it was A...because C sounded a bit awkward...

anonymous · Answer

no because in a who are they talking about?

anonymous · Answer

the sister..

anonymous · Answer

good question.

coldplay · Answer

A. lol

anonymous · Answer

I think its c

anonymous · Answer

in a it seems like a run on sentence and it really needs a comma

coldplay · Answer

ColdPlay says its C. Please vote

coldplay · Answer

I remember saying it was A. but now that I am thinking of it, I say its C.................... please vote thanks so much I love you Taylor......................