Final answer:
An OIC in the grades of E7 or E8 can generally sign reports for individuals at their grade and below, which would include pay Grade E7. However, without specific military branch context, a definitive answer may not be determined.
Step-by-step explanation:
The question relates to the authority levels within the military ranking system, specifically which reports an Officer in Charge (OIC) with a grade of E7 or E8 can sign off on. In the military, individuals with higher ranks typically have the authority to sign reports for those at lower ranks. Without specific military branch context, it's generally safe to assume that an OIC in pay grades E7 or E8 may sign reports for individuals at their grade and below. This would suggest that they can sign reports for individuals in the pay Grade E7 and below, but not for those in a higher or equivalent grade such as E8 or above. Therefore, the answer to the question is most likely 2) E7. However, as military protocols can vary across different branches and specific duties, the answer 4) Cannot be determined might be applicable if the context is not clear.