why do you think this is the case? what can scientist learn about los angeles climate history by studying the specimens found it there tar pits?​

The answer is A) The relative frequency of the mutation will increase as time passes. 

In natural selection, genotype variations that will increase the chance of survival and reproduction of some organism are preserved and will be inherited. So, the mutation could not be abnormal, since it helps bacterial survival. Also, the bacteria will not extinct because of this mutation nor the new species will be formed since this is not so big mutation.
This leaves A) as the right answer. The relative frequency of the mutated allele will increase since the more bacteria with the mutation will survive and it will be passed down to the new generation over time.