An allele that is relatively new to a population and has been subject to positive natural selection is characterized by having .

High frequency and High linkage disequilibrium

Explanation: Natural selection is a process whereby an people with a with a specific genotype are more likely to survive and pass their alleles to their next generation that people with another type of genotype. Natural selection can also influence the frequency of and allele by either causing and increase or decrease of that allele's frequency.

i am positive it is c. condensing but i may be wrong