answer is (b). Since we are assuming that the order of B and B+ is the same, so each node of b tee and b+ tree both, will contain same number of keys.Now b+ tree will have to contain repeated keys in internal nodes so no. of levels will increase for b+ tree. Had the order not been the same, we could have assumed higher fan out of b+ tree increasing breadth and decreasing height and in that case B tree would have larger number of levels than B+ tree