Chapter 9 - Section 9.9 - Exceptions to the Octet Rule: Odd-Electron Species, Incomplete Octets, and Expanded Octets - Conceptual Connection - Page 411: 9.7

The correct answer is (b) $H_3PO_4$

Among the 4 given options, phosphorus ($P$) is the only third-period element. So, only $H_3PO_4$ can have an expanded octet. Second-period elements like carbon and nitrogen never form compounds with expanded octets.