Acompany develops a new pesticide that kills insects. when the pesticide is first used, it kills nearly all the insects.

which statement explains why after 10 years, nearly all the insects can tolerate the pesticide and survive?

a.
at first, most of the insects were resistant to the pesticide. only the few insects that were resistant to (or could tolerate) the pesticide survived and reproduced, but did not pass any of these traits to their offspring.

b.
at first, none of the insects were resistant to the pesticide. over time, a few of the insects became resistant to (or could tolerate) the pesticide survived and reproduced, but did not pass any of these traits to their offspring.

c.
at first, most of the insects were sensitive to the pesticide. only the few insects that were resistant to (or could tolerate) the pesticide survived and reproduced, passing on traits that them survive.

d.
the company needed to apply another application since all of the insects were immediately resistant to the pesticide. those resistant insects survived and reproduced, passing on traits that them survive onto their mutant offspring.