What is the buddy allocator and what problem does it solve? Select the most accurate answer.

a) The buddy allocator is a memory allocator that allocates memory in fixed size blocks. As all allocations are of identical size, external fragmentation cannot occur.

b) The buddy allocator is a memory allocator that splits blocks into smaller blocks when they are freed. This approach makes it more efficient to handle variable-size allocations.

c) The buddy allocator is a memory allocator that allocates memory in blocks of sizes that are powers of two. Compared to an allocator using arbitrary variable allocation sizes, this approach may result in higher internal fragmentation, but reduces external fragmentation.

d) The buddy allocator is a memory allocator that groups memory allocations for objects of a specific type. The advantage of the buddy allocator is a better cache locality.