answer the question Please ASAP

The independent variable is
A: Number of friends (f)
B: Number of cost (c)

The dependent variable is
A: Number of friends (f)
B: Number of cost (c)

The equation that can be used to represent this relationship:
A: c = 20f
B: f = 20c
C: c = 10f
D: f = 10c

answer the question Please ASAP The independent variable is A Number of friends f B Number of cost c The dependent variable is A Number of friends f B Number of class=