20 POINTS! ANSWER CORRECTLY FOR BRAINLIEST!

Which of these is a similarity between a polar and a subtropical jet stream?
A. Both are formed at latitudes close to the poles.
B. Both are formed at latitudes close to the equator.
C. Both are formed at the boundary of warm and cool air masses.

(D not included because I know for a fact it is incorrect, I honestly think the answer is C but I just want other peoples opinions)