Below are some alternatives which may be used to improve the sentence by…

In a sentence-improvement question, a suggested word replaces the original only if it conveys the intended meaning at least as accurately; when every alternative distorts or misses that meaning, the original word is retained and the correct choice is 'No improvement'.

The sentence describes a child who cannot play with the other kids and, as a result, feels sadness. The word 'depressed' — meaning in a state of unhappiness — precisely captures this feeling, so each alternative must be checked against that same meaning:

• Jolly means cheerful and happy — the opposite emotion, so it does not fit a situation that causes sadness.

• Cautious means careful to avoid danger — an unrelated idea, not an emotion caused by exclusion from play.

• Reductive means tending to oversimplify a problem or argument — a description of an idea, not a feeling.

• Drastic means extreme or severe, usually describing an action or change — not an emotional state.

Since none of the four alternatives preserve or improve the sadness conveyed by 'depressed', the original sentence needs no change — 'No improvement' is the correct choice.