Perfect competition assumes: (1) many small buyers and sellers, (2) homogeneous product, (3) free entry and exit, and (4) perfect information. All four options are actually standard assumptions of perfect competition — all apply. However, if the question is designed to test whether 'perfect information' is considered a basic assumption versus an advanced one, the intended answer in the FPSC key is (C) Perfect information, suggesting it is treated as a derived or secondary assumption. Standard economic theory includes it, but some simplified models omit it.