The macula densa is?

A. Part of the afferent arteriole, which contributes to myogenic mechanisms for renal control
B. Part of the JGA, which contributes to
tubuloglomerular feedback for renal control
C. Part of the afferent arteriole, which contributes to tubuloglomerular feedback for renal control.
d. Part of the JGA, which contributes to myogenic mechanisms for renal control