Which one of the following options is the closest in meaning to the word given…

Concept: A synonym question asks for the option whose meaning is closest to the given word. The method is to recall the precise sense of the headword, then match it against each option's meaning, remembering that an antonym (opposite-meaning word) is a common trap.

Applying it: 'Nadir' denotes the bottom-most or deepest point of something. It is used literally (the point on the sky directly beneath an observer, opposite the zenith) and figuratively (the worst or most depressed moment of a situation), as in "After the scandal, the team's morale reached its nadir." The option that captures this bottom-most sense is the right choice.

Contrasting the other choices:

• 'Highest' is the direct opposite of 'nadir'; the term for the topmost point is 'zenith', so it is an antonym, not a synonym.

• 'Medium' means a middle or average position, not an extreme, so it does not match the bottom-most sense of 'nadir'.

• 'Integration' refers to combining parts (or a mathematical operation) and has no relation to the idea of a deepest or bottom point.

Result: The choice closest in meaning to 'nadir' is the one denoting the bottom-most point.