Assigning a value of $20$ to the objective function, i$.$e$.,$ making $4x_1+20x_2=20$ the line for the objective function goes through the following two points

$(1,0)$ and $(5,0)$

$(0,1)$ and $(0,5)$

$(1,0)$ and $(0,5)$

$(5,0)$ and $(0,1)$

none of the above