For function f(x), which condition implies a horizontal asymptote at y = 31?

A horizontal asymptote describes the value that f(x) approaches as x becomes very large or very negative. In choice B, the limit of f(x) as x approaches infinity is 31, so the graph approaches the horizontal line y = 31. A limit as x approaches 31, as in choice A, concerns behavior near a particular input, not a horizontal asymptote.

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