I ought to tell the truth because the only way I could lie and get away with it is if people generally are honest. I would be expecting others then to behave in ways that I myself would not.

a. Hypothetical
b. Categorical

CATEGORICAL.

Explanation: Categorical imperative in ethics refers to fundamental ethical principle intended as a guide for determining whether any contemplated action is morally right, based on the concept that an action is good or bad in and of itself regardless of what the actor's aims or preferences are.

From the definition above, it can be deduced that the statement "I ought to tell the truth because the only way I could lie and get away with it is if people generally are honest. I would be expecting others then to behave in ways that I myself would not." is a Categorical imperative.

taking a bath requires the most water out of the given options because it takes a significant amount of water in order to fill a bathtub.

it's the under parts of the car