In each of the following questions, choose the option that best completes the gap(s). She is ______ a sailor who is away at sea.

This question tests phrasal verbs and collocations. The sentence describes a woman's feelings towards a sailor who is away at sea, and the correct completion must fit both the grammar and the emotional context.

The phrase longing for means deeply yearning or missing someone. It perfectly captures the emotional state of someone whose loved one is away at sea for extended periods. "She is longing for a sailor who is away at sea" conveys a deep, emotional desire for the sailor's return.

While the other options are grammatically possible, they do not best fit the context:

• fuming about means being very angry about someone, which does not match the tone of the sentence.
• waiting for is neutral and does not convey the depth of emotion implied by the scenario of a sailor being away at sea.
• writing to describes a physical action (correspondence) rather than an emotional state, and the sentence structure with the present continuous ("She is...") favours an emotional or psychological state.

"Longing for" is the collocation that best conveys the yearning associated with prolonged separation.