Think of "capitulate" in a war or argument setting: a side that capitulates stops fighting and accepts defeat. The antonym should describe a side that keeps fighting instead.
"Summarize" belongs to writing and speaking, not to conflict, so it cannot be an opposite here. "Deride" is about making fun of someone, again unrelated to surrender. "Disobey" is closer, since it involves defiance, but it is usually about ignoring a rule or order rather than continuing a struggle.
"Resist" precisely captures a side holding its ground and refusing to surrender, which is the true opposite of "capitulate".
The correct antonym is therefore option C, "Resist".