Answer:
the third option
Explanation:
the 5 pounds weight at birth is the starting value.
so, the function needs to have a constant part of at least +5.
and every month 0.5 pounds are added.
that is exactly the situating to use multiplication : weight gain per month times the number of months (plus the starting value of 5 pounds) delivers the weight after a certain number of months.
w = weight after t months
t = number of months measured