Which statement about the best estimation strategy for this problem is correct?

there are twice as many boys as girls at the camp. there are 62 boys. how many children are at the camp?

bob said there are 124 children at the camp.

a.
to estimate use the equation 60 + 60 ÷ 2 = n.
bob's answer is not reasonable.

b.
to estimate use the equation 60 × 2 = n.
bob's answer is reasonable.

c.
to estimate use the equation 60 × 3 = n.
bob's answer is not reasonable.

d.
to estimate use the equation 60 + 60 + 60 = n.
bob's answer is reasonable.