An interesting question because it’s equating units and square units. At least they had the courtesy / good sense to include the word “value” so we know they’re just talking about the numeric result, not the physical / mathematical reality of what the results mean.
See this thread for a mild religious war about math problems of this nature:
As to this problem specifically, as @slalexan says, it’s trivial and needs no multiple choice.
Mechanically converting the words of the problem into an equation yields:
4S = S^2. Solve for S.
By inspection S=4.
And of course zero is a degenerate answer as well. Also by inspection. Any equation involving just multiplication and exponentiation is trivially solved at zero.