Which sentence is the correctly written compound sentence?

A.
In the spring, my sister helps the marching band sell flowers to raise money.

B.
In the spring the marching band sells flowers to raise money.

C.
My sister is in the marching band, and in the spring they sell flowers to raise money.

D.
My sister is in the marching band, in the spring they sell flowers to raise money.

Question

Which sentence is the correctly written compound sentence?
 
 A.
In the spring, my sister helps the marching band sell flowers to raise money.
 
 B.
In the spring the marching band sells flowers to raise money.
 
 C.
My sister is in the marching band, and in the spring they sell flowers to raise money.
 
 D.
My sister is in the marching band, in the spring they sell flowers to raise money.

mrhirohito · Answer

C.
My sister is in the marching band, and in the spring they sell flowers to raise money.

flower2468 · Answer

I think that is correct