Scarlet Gilia (Ipomopsis Aggregata) Usually Has Red Flowers in an Inflorescence

Scarlet gilia (Ipomopsis aggregata) usually has red flowers in an inflorescence of up to 250 flowers. In certain populations in the Arizona mountains, however, the flowers range from red to pink to white. In early summer, most (but not all) of the flowers were red. Six to eight weeks later, the same individual plants were still present; the flowers ranged from pink to white, and few red flowers were present. The major pollinators early in the season were two species of hummingbirds active during the day; they emigrated to lower elevations, and the major pollinator later in the season was a hawk moth (a type of moth) . The hawk moth was most active at sunset and later, and it preferred light pink to white flowers after dark. When hummingbirds were present, more red flowers than white flowers produced fruit. When only hawk moths were present, more white flowers produced fruit. (K. N. Paige and T. G. Whitham. 1985. Individual and population shifts in flower colour by scarlet gilia: A mechanism for pollinator tracking. Science 227:315-17) .
-What is the significance of measuring fruit production?

A) It is a measure of pollination success.
B) It is a measure of seed dispersal success.
C) It is easier than counting flowers.
D) It is an indication of predation on the seeds of the plants.