A Water Plant Gets Wrapped Around the Propeller of a Boat

Multiple Choice

A water plant gets wrapped around the propeller of a boat in Round Pond. This particular plant exhibits an unusual allele that gives it extra branches. The boat owner moves his boat to Big Lake without cleaning the plant off the propeller. The same species of water plant already exists in Big Lake, but none of the plants exhibit the "extra branches" allele. One year later, the frequency of the extra branches allele in Big Lake is much higher. This is an example of

A) genetic drift.
B) mutation.
C) natural selection.
D) gene flow.