The graphs below which shows (a) change in barn swallow road kills and nest abundance, and (c) mean wing length of road killed birds and the whole population in connecticut between 1984 and 2012. what is the most likely explanation for the trends depicted?

a.
vehicles are inducing strong positive selection for swallows with short wings by vehicles
b.
swallows are unable to adapt to changing conditions brought about by vehicular traffic
c.
the swallows are experiencing strong disruptive selection for long and short wings
d.
the barn swallow population is in steep decline due to excessive road kills
e.
the number of road kills has declined dramatically due to the smaller population size of swallows