A d$-$heap is a tree with the property that a parent's value is smaller than $($or equal to$)$ the value of any of its $d$ children. We assume that the $d-$heap has $N$ elements.

Select one or more:

a$.$ Printing $\frac{N}{2}$ elements in order costs $O(N^2)$

b$.$ Printing the kth smallest element costs $O(N^k)$

c$.$ The $d-$heap might degenerate after a series of insert operations

d$.$ The d$-$heap might degenerate after a series of deletemin operations

e$.$ The largest element must be one of the leaf nodes

f$.$ The largest element is a d$-$heap can be found in $O(lo{g}_{d}N),$ in the worst case.