I think the answer might be C, but I'm not 100% sure.
hmmm let's find the distance between B and C first off.
hmmm if BC is that much, then AB + AC = 7, since AB + AC + BC = 12 which is the perimeter, Check the picture below.
this is a binomial problem: p = 0.7 and q = 0.3
a) (0.7)^6
b) (6C4)(0.7)^4(0.3)^2
c) Pr ( at least 4) = Pr(4) + Pr(5) + Pr(6) = (6C5)(0.7)^5(0.3) + (0.7)^6
d) Pr (no more than 4) = 1 - Pr(at least 4) = 1 - (answer from c)