For the value of 'y' to equal ZERO (all of the points are x-intercepts and thus = 0 ) i.e. f(x) =0
then "D"
f(x)= 0 = (x+1) (x+2)(x-3) So at least ONE of the factors must equal 0
(x+1) = 0 would mena x = -1
(x+2) = 0 would mean x = -2
(x-3) = 0 would mean x = 3 so answer D