Directions: Select the most appropriate word to fill in the blank. Only a…

Concept

In a sentence-completion item built on a parallel structure such as "X are A; the rest are B," the blank must satisfy two conditions at once: it must match the part of speech and category required by the slot (here, a plural noun naming a group of people), and it must create the logical contrast the sentence sets up between A and the rest.

Application

The sentence contrasts "convicts" — people already tried and found guilty — with "the rest." To complete the contrast, the blank must name the other category of people held in custody: those whose trial has not yet concluded. That is exactly what "under-trials" means — people who are being held in custody while awaiting or undergoing trial.

Cross-check (why the other options fail)

• "Underpopulated" is an adjective describing a place that has too few people in it — it cannot itself name a category of people, so it cannot stand in the noun slot that pairs with "convicts."

• "Understated" describes something expressed with restraint (e.g., "an understated remark") — it describes a manner of expression, not a group of people.

• "Underwhelmed" describes a person's feeling of being unimpressed — an emotional state, not a custodial or legal category, so it cannot contrast with "convicts."

Complete sentence: "Only a small fraction are convicts; the rest are under-trials."