Point out the mismatched pair with respect of the Sale of Goods Act:

Sale by a person who is not the owner is dealt with by section 27, not section 31, of the Sale of Goods Act, 1930, so "sale by person not the owner Section 31" is the mismatched pair; "caveat emptor Section 16", "risk prima facie passes with property Section 26" and "sale by sample Section 17" are all correctly matched.