Answer:
b
Step-by-step explanation:
In this scenario, brown eyes are dominant to green eyes. Lets say that the (dominant) allele for brown eyes is G and the (recessive) allele for green eyes is g. Both parents are heterozygous, so their genotype is Gg.
To work out the probability of having one child with green eyes, we do a punnet square (attached). 3 out of the 4 possible genotypes give brown eyes (GG or Gg) only 1 out of 4 gives green eyes (gg).
The probability of 1 child having green eyes is 25%. The probability of 3 children having green eyes is 0.25 x 0.25 x 0.25 = 0.0156, which is equal to 1.6%.
This is called the "product rule" - the probability of 2 independent events occurring together is calculated by multiplying the individual probabilities of the events