Choose the exact meaning of the idiom/phrase. In deep water

in a lot trouble: is the correct option as the phrase in deep water 'means to be in trouble.
to feel lonely: is an incorrect option because it means to feel alone when someone around is not there.
to act like a coward: is an incorrect option because it means not to do something due because the one doesnt have enough courage to do so.
to swim in a river: is an incorrect option because it means to propel the body through water by using limbs or in the case of aquatic animals, it can be done by fins, tail, or other body movements.