B+ Tree

Question

In a B+ tree index file if there are K search keys and each leaf node contains n records then number of records to be accessed in the worst case is

a)log₂n^k

b) log_nk

c)log_ceil(k)n

d)log_ceil(n/2)k

Here ceil is ceiling function

Answer 1

Ans will be D) logceil(n/2)k

but dont know the explanation for this :D .