Some individuals have a mutated recessive allele and a homozygous individual is resistant to hiv infection and aids. some populations have a high frequency of the mutant allele. what inference can be made about the mutant allele? a. heterozygous individuals must be genetically advance even if they are not resistant to hiv b. the mutated allele must have developed and been acquired by many people before exposure to the virus . c. the mutated allele must not be inherited by offspring or disease would be close to eradication d. being a homozygous is a advantage for mutated allele , while being heterozygous is genetic advantage

Correct B.
We know that some populations have a high frequency of the mutant allele, which indicates that there was already a wide spreading of it so that when the disease attacked the population, cause the necessary selection to promote the high frequency of the mutant allele. If the mutant allele appeared only when the disease struck, the mutant allele frequency wouldn't be high because this is a process that takes time.

We can't be sure that A. is true, we'd need more information as to whether there is any advantage in having at least one allele. We do know that it is a recessive allele, therefore, most likely, there isn't any advantage.
C. - we can't foresee whether the disease would come to a closure. The virus could evolve alongside with the selection and this mutated allele would not be of any use.
There is only a genetic advantage - D. - in being heterozygous if there is an advantage having only one mutated allele, which we don't know. 

The answer is option a