What would be the number of chromosomes in the cells of the aleurone layer in a plant species with 8 chromosomes in its synergids?

The correct option is B 24
Synergids are part of the embryo sac and therefore are haploid (n). The endosperm formed from this embyro sac will be triploid (3n) due to triple fusion. The aleurone layer is the outermost layer of the endosperm and therefore it is triploid.
It is given that number of chromosome in the synergids is 8 i.e n = 8. Therefore the number of chromosmes in the aleurone layer would be 3n = 3 x 8 = 24.