Select the most appropriate option that can substitute the underlined words in…

Concept: A one-word substitution replaces a whole descriptive phrase with a single word that carries the same core sense and fills the same grammatical slot. Two tests settle such an item: does the candidate exist as an English word with a settled dictionary meaning, and does that meaning match the sense the sentence actually needs, rather than a neighbouring idea borrowed from the same subject area?

Application: Here the underlined phrase is an adjectival complement of "turn" (turn a patient completely ___), so the substitute must be a single adjective describing a body that shows no sign of life. "Cadaverous" is built on the Latin noun cadaver, "a corpse", and is used of a face or body that looks pale, gaunt and corpse-like. Of the four candidates it is the only one drawn from the sense-field of death and lifelessness, which is why it carries the force of "lifeless and unresponsive" here; strictly, it names the deathlike look and condition rather than unresponsiveness on its own.

Contrast: The remaining candidates belong to different sense-fields:

• "Tombic" is a rare adjective formed from "tomb", meaning "of or like a tomb"; it characterises the burial structure, not a person’s physical condition.

• "Zonic" is an obsolete adjective formed from "zone", meaning "zonal, relating to zones"; it has no bearing on health or appearance.

• "Wasted" means thinned or shrunken by illness, hunger or prolonged strain; it reports a slow loss of flesh rather than the corpse-like lack of response the sentence describes.

Cross-check: Read the word back into the sentence: "the heavy medications and strong drugs at the sanatorium will surely turn a patient completely cadaverous" keeps the sentence idiomatic and retains the sense of the underlined phrase, while none of the other three candidates yields a meaningful reading. That is what confirms the substitution.