Which of the following is best example a latent function going to college?

The best example of a latent function of going to college is finding a spouse or long-term partner.

Latent functions are unintended and often unrecognized consequences of a social pattern or institution. While the manifest (intended) function of college is to gain an education and improve job prospects, meeting a partner is a byproduct that isn't the primary reason people attend. Other options might have some latent aspects, but finding a spouse is a more purely latent function.