On the first down the team returned the ball to the 30 yard line, then they ran the 42 yard line for a gain. which number represents the change? (number line is on pic)

a. -12
b. 0
c. +4
d. +12

Hi, can someone please help me with this? I’ll give branliest if i can!

On the first down the team returned the ball to the 30 yard line then they ran the 42 yard line for a gain which number represents the change number line is on class=