Which of the following actions would likely yield the highest utility?

Choosing to pay for a college education is likely to yield the highest utility because education generally leads to long-term benefits, such as higher earning potential, job stability, and personal growth. By investing in one's education, an individual enhances their skills and knowledge, making them more competitive in the job market. This can result in better job opportunities, increased salary potential, and overall improved quality of life over time.

While the other options can also provide utility, they tend to offer more immediate but potentially less sustainable benefits. For example, investing in a small business can be rewarding but carries risks and may not guarantee high utility if the business doesn't succeed. Buying a new phone provides instant gratification and satisfaction but does not significantly impact long-term financial or personal growth. Going on a vacation can offer momentary joy and experiences but does not contribute to increased earning potential or job skills.

Thus, in the context of long-term utility and benefits, investing in education stands out as the choice most likely to yield the highest utility overall.