The line A passes through two points, those are:
(x₁,y₁) = (0,4)
(x₂,y₂) = (-7,0)
Use the following formula of slope
m = (y₂ - y₁) / (x₂ - x₁)
Plug the numbers into the formula
m = (y₂ - y₁) / (x₂ - x₁)
m = (0 - 4) / (-7 - 0)
m = -4/-7
m = 4/7
The answer is option c