Improve the bracketed part of the sentence by choosing the most appropriate phrasal verb: Rohan was upset and so (picked up) his food while his cousins ate heartily.

Introduction / Context:
This question checks your understanding of phrasal verbs that describe eating behaviour. In spoken English, we often use specific phrasal verbs to show whether someone is eating cheerfully, eating a lot, or eating very little. The sentence describes Rohan, who was upset and therefore did not eat properly while his cousins enjoyed their food. You must choose the phrasal verb that precisely describes eating in a half hearted, unenthusiastic way.

Given Data / Assumptions:
- Rohan was upset, so his emotional state was negative.
- His cousins ate heartily, meaning they ate with enthusiasm and appetite.
- The bracketed phrase "(picked up) his food" is to be improved.
- The correct option should express that he ate reluctantly or only in tiny amounts.

Concept / Approach:
Phrasal verbs are combinations of a verb and a preposition or adverb that create a specific idiomatic meaning. "Pick at" food means to eat very little and without enthusiasm, usually because the person is upset or not hungry. "Pick up" food usually means to lift or collect it, not to eat reluctantly. "Pick on" means to bully or tease someone. "Pick out" means to select one item from many. For this sentence, the emotional context points clearly towards the idiom that conveys half hearted eating.

Step-by-Step Solution:
Step 1: Note the cause: Rohan was upset, which normally reduces appetite. Step 2: Compare his behaviour with that of his cousins, who ate heartily. Step 3: Interpret what the sentence wants to show: that he ate very little or only moved the food around. Step 4: Check meanings of the phrasal verbs. "Pick at food" is a fixed expression that describes eating very little and without interest. Step 5: Substitute "picked at" into the sentence: "Rohan was upset and so picked at his food while his cousins ate heartily." The meaning now fits perfectly.

Verification / Alternative check:
Try each option in the sentence. "Picked out his food" would mean he selected his food, which does not match the contrast with "ate heartily". "Picked on his food" is grammatically unnatural. "No improvement" keeps "picked up his food", which simply describes lifting the plate or food, not his style of eating. Only "picked at his food" clearly shows that he barely ate because of his mood.

Why Other Options Are Wrong:
- "Picked out": Focuses on choosing something, not the act of eating reluctantly.
- "Picked on": Refers to teasing or bullying a person, not food at all.
- "No improvement": The original phrasal verb does not convey the intended idea of poor appetite.

Common Pitfalls:
Learners often look only at grammatical correctness and ignore idiomatic usage. Another common mistake is to assume that any phrasal verb with "pick" is interchangeable, which is not true. English phrasal verbs are highly idiomatic and usually have fixed meanings that must be learned with examples.

Final Answer:
The correct improvement is Picked at, because it accurately describes Rohan eating very little and without enthusiasm due to being upset.