The diagram given below represents the operation of natural selection on different traits. Choose the correct option.

Random genetic drift in a population probably results from

In natural selection,more individuals acquire value other than the mean character value,which indicates . . . . . . .

'$A$ brief reduction in size of a population,due to natural calamities,usually leads to random genetic drift'. For this statement,identify the correct example from the following.

Assertion : Natural selection is the outcome of difference in survival and reproduction among individuals that show variation in one or more traits.
Reason : Adaptive forms of a given trait tend to become more common; less adaptive ones become less common or disappear.

Given below are two statements.
Statement-$I$: Elimination of particular alleles from a population due to natural disasters is called genetic drift.
Statement-$II$: Sudden temporary heritable change in the gene is called point mutation.
In the light of above statements,choose the most appropriate answer from the options given below: