Choose the option that best expresses the meaning of the idiom Feather one's own nest, which describes a particular kind of behaviour.

Introduction / Context:
This question tests comprehension of the idiom feather one's own nest, which appears in discussions about self interest, corruption, and misuse of position. Idioms often have figurative meanings that go beyond the literal image created by the words. Here, the idiom suggests that a person is using their position or opportunities mainly to enrich themselves, especially in a way that may be dishonest or morally doubtful. Understanding such idioms is important for interpreting newspaper reports and critical commentary.

Given Data / Assumptions:

• Idiom given: Feather one's own nest.
• Options: Decorate, Work hard at home, build a home, make money in an improper way.
• No sentence is provided, so we rely on the standard figurative meaning.
• The task is to select the explanation that captures the negative moral judgment implied by the idiom.

Concept / Approach:
Literally, birds feather their nests by bringing soft materials to make them comfortable. In the idiom, a person is said to feather their own nest when they use their position, power, or opportunities primarily to increase their personal wealth or comfort, often through unfair, corrupt, or selfish means. The expression is usually used critically. The correct option therefore needs to reflect the idea of gaining money or benefits for oneself in a questionable way, rather than simply decorating or building a home.

Step-by-Step Solution:
Step 1: Recall the figurative meaning of the idiom: to profit oneself at the expense of others, often dishonestly. Step 2: Read the options and identify any that mention making money, which is central to the idiom. Step 3: Option D states make money in an improper way, which fits both the money aspect and the negative moral judgment. Step 4: Option A, Decorate, focuses only on appearance and does not involve money or selfish gain. Step 5: Option B, Work hard at home, suggests effort but not self enrichment through misuse of position. Step 6: Option C, build a home, is a literal interpretation and ignores the figurative meaning of the idiom. Step 7: Conclude that Option D correctly represents the figurative meaning of the expression.

Verification / Alternative check:
To verify, consider example sentences such as critics accused the minister of feathering his own nest while in office. This clearly does not mean he decorated his house or worked hard at home; it implies he used his official role to gain personal wealth. Another example is instead of working for the welfare of the company, he has been feathering his own nest. Again, the focus is on selfish financial advantage, often with an unethical aspect. These examples confirm that the idiom refers to making money or securing advantages for oneself in a way that others may view as improper or corrupt.

Why Other Options Are Wrong:
Decorate: While nests and homes can be decorated, the idiom is not about interior design but about selfish financial gain.
Work hard at home: This phrase suggests diligence but does not involve the idea of misusing power to enrich oneself.
build a home: This is a literal construction activity and does not capture the figurative, critical meaning of the idiom.

Common Pitfalls:
Learners may be misled by the literal image of a nest and assume that the idiom relates to making a home comfortable. Another pitfall is not recognising the negative moral tone present in many idioms that describe selfishness or corruption. To avoid such errors, it is important to learn idioms in context, notice the tone in example sentences, and remember that many idioms describe character or behaviour rather than physical actions.

Final Answer:
The idiom Feather one's own nest means make money in an improper way.