Given below are two statements – one is labelled as Assertion (A) and the other is labelled as Reason (R):
Assertion (A): Human adeno-associated virus is used to deliver single-stranded DNA as a vaccine that does not require multiple booster doses.
Reason (R): Such vaccines are generally administered along with an adenovirus or a herpesvirus to avoid multiple booster doses.
In light of the above statements, choose the most appropriate answer from the options given below:
For \( n \in \mathbb{N} \), the largest positive integer that divides \( 81^n + 20n - 1 \) is \( k \). If \( S \) is the sum of all positive divisors of \( k \), then find \( S - k \).
If Planck's constant is \( 6.63 \times 10^{-34} \) Js, then the slope of a graph drawn between cut-off voltage and frequency of incident light in a photoelectric experiment is: