A page replacement algorithm suffers from Belady's anamoly when it is not a stack algorithm.
A stack algorithm is one that satisfies the inclusion property. The inclusion property states that, at a given time, the contents(pages) of a memory of size k page-frames is a subset of the contents of memory of size $k+1$ page-frames, for the same sequence of accesses. The advantage is that running the same algorithm with more pages(i.e. larger memory) will never increase the number of page faults.
Is LRU a stack algorithm?
Yes, LRU is a stack algorithm. Therefore, it doesn't suffer from Belady's anamoly.
Ref : Ref1 and Ref2
Is Random page replacement algorithm a stack algorithm?
No, as it may choose a page to replace in FIFO manner or in a manner which does not satisfy inclusion property. This means it could suffer from Belady's anamoly.
$\therefore$ (B) should be answer.