To determine which sentence describes a person who is the opposite of Manuel, we need to know what characteristics Manuel has. Since this information is not provided, we can make some assumptions based on common contrasts.
If Manuel is described as thin, short, old, etc., then the opposite would be something like 'gordo' (fat) if he is thin, 'bajo' (short) if he is tall, 'viejo' (old) if he is young, and 'joven' (young) if he is old.
Given the options: A. César es muy gordo. B. César es muy bajo. C. César es muy viejo. D. César es muy joven.
Without knowing Manuel's specific traits, it's impossible to select the correct opposite definitively. However, if we assume Manuel is neither old nor young, then option D (César es muy joven) would be the opposite of an 'old' Manuel. Alternatively, if Manuel is fat, then A would be also the opposite.
Please provide more context about Manuel for a precise answer. Otherwise, if we assume Manuel to be old, choose D. If he is thin, choose A.