TurboTax is asking me about K-1, Box 14, and wants to me to pick from a list of choices for "income category." Options include "passive", "general", etc. K-1 Doesn't say.

What was the K-1 for? Were you actively engaged in the business operation?

Form 1041. I was not actively engaged, this was a trust-run operation - I received beneficiary income.

What generated the income? Investments? Rental property? Mining?

Investments

If the trust's income was generated from investments, the correct income category would be "passive".