John works as a professional Ethical Hacker. He has been assigned a project to test the security of www.we-are-secure.com. On the We-are-secure login page, he enters =’or”=’ as a username and successfully logs in to the user page of the Web site. The We-are-secure login page is vulnerable to a__________.
A. Replay attack
B. Land attack
C. SQL injection attack
D. Dictionary attack