In the following question, out of the four given alternatives, select the one which best expresses the meaning of the given word: Incumbent.

Introduction / Context:
This vocabulary question asks you to choose the option that gives the closest meaning to the word incumbent as used in formal English. While incumbent can also refer to someone currently holding an office, in many exam questions it is used in the sense of something being necessary or obligatory. You must recognise which sense fits the options provided.

Given Data / Assumptions:

• Target word: incumbent.
• Options: Increase, Redundant, Choice, Required.
• No sentence is given, so we look at dictionary meanings and see which option matches one of them.
• Common meaning in moral or legal contexts: incumbent on someone = required as a duty.

Concept / Approach:
Incumbent, when followed by on or upon, means necessary, required or obligatory as a duty or responsibility. For example, “It is incumbent on all citizens to obey the law” means it is required of them. Among the given options, Required matches this sense directly. Increase relates to growth, redundant means unnecessary, and choice refers to an option or selection. None of these except Required carries the idea of duty or obligation.

Step-by-Step Solution:
Recall key usage: “It is incumbent on you to submit the form on time” = “It is required of you.”Compare this with each option:Increase – does not mean duty, just growth in size or number.Redundant – means not needed, the opposite of required.Choice – means an option among several possibilities.Required – directly reflects something that must be done or fulfilled.Thus, the best synonym for incumbent in the duty sense is Required.

Verification / Alternative check:
Consider the phrase “an incumbent duty”. If we paraphrase as “a required duty”, the meaning remains the same: a duty that you must perform. If we try “an increase duty” or “a redundant duty” or “a choice duty”, these phrases either do not make sense or completely change the meaning. This confirms that Required is the only option that works as a substitute for incumbent in this exam context.

Why Other Options Are Wrong:
Increase focuses on rising quantities and has no connection with obligation. Redundant actually means superfluous or unnecessary, which clashes with the idea of something being binding or compulsory. Choice indicates freedom to select, which suggests the opposite of compulsion. Therefore, none of these three conveys the central idea of an obligation that is incumbent on someone.

Common Pitfalls:
Students sometimes only remember incumbent in political news (“incumbent prime minister”), where it means “currently holding office”. Without a sentence to guide the meaning, you must rely on the options. Here, no option relates to current office, so the exam expects you to know the secondary meaning of incumbent as “required or obligatory”. Learning both senses and linking incumbent on with required of will help you address such synonym questions with confidence.

Final Answer:
The word that best expresses the meaning of “Incumbent” (in the sense tested here) is Required.