In a B+ tree, the requirement of at least half-full (50%) node occupancy is relaxed for which one of the following cases?

In a $\text{B}^+$ tree of order $p$:

• Every internal node (except the root) has at least $\lceil p/2 \rceil$ children and at least $\lceil p/2 \rceil - 1$ keys.

• Every leaf node (except when the root is the only node) contains at least $\lfloor p/2 \rfloor$ (or $\lceil (p-1)/2 \rceil$) key-pointer pairs.

• The root node is an exception to the minimum occupancy rule: if it is not a leaf, it needs to have at least $2$ child pointers (and at least $1$ key), and if it is a leaf (i.e., the entire tree has $\le p-1$ records), it can contain as few as $1$ search key value (or even $0$ if the tree is empty).

Therefore, the requirement of at least half-full node occupancy is relaxed only for the root node.

Thus, (A) is the correct option.