Answer: c. The positive control tube receives any genomic DNA from a student's sample that is predicted to be infected with Wolbachia.
Step-by-step explanation:
Positive PCR control can be defined as the control sample that is used as a benchmark for comparison with the results of the PCR or polymerase chain reaction. It comprises of artificial genome or primers. For amplification of microbial DNA synthetic oligonucleotides are used as targets of each primer and a hydrolysis probe is also used. As it is already known that primer as well as hydrolysis probe has the specificity for the DNA strand so it will help in identification of the specific region or sequence in the DNA structure. Wolbachia DNA can be detected if the positive control consists of samples of students affected by Wolbachia that can give indication of whether the Wolbachia species is the same as that of the one which has caused infection.