In the following question, an idiom is given. Choose the option that best expresses the meaning of the idiom "grease the palm". This expression frequently appears in discussions about money and corruption.

Introduction:
Idiomatic expressions often use physical images to describe social or moral actions. The idiom "grease the palm" is commonly associated with corruption and illegal payments. This question checks whether you can connect this idiom with its real meaning, which is very important in reading newspapers and understanding current affairs articles.

Given Data / Assumptions:
- Idiom given: "grease the palm".
- Options: "dirty one's hands", "work in a garage", "slip and fall", and "bribe".
- We assume that the context is about giving money secretly to get a favour done faster or unfairly.

Concept / Approach:
The phrase "grease the palm" suggests putting something smooth or oily on someone's hand, which in idiomatic usage stands for slipping money into someone's hand. Over time, it has come to mean paying a bribe. It does not refer literally to oil or to physical work. The approach is to identify the option that clearly refers to bribery, that is, giving money in order to influence someone's actions.

Step-by-Step Solution:
Step 1: Recall typical sentences, such as "He had to grease the official's palm to get the file cleared quickly."Step 2: In such contexts, the meaning is clearly that he paid an illegal or improper amount of money.Step 3: Look at option D, "bribe". To bribe someone is to give money or a favour in order to persuade them to act in your interest, especially unfairly.Step 4: Compare with option A, "dirty one's hands", which is more general and can mean getting involved in any kind of wrongdoing, not specifically paying money.Step 5: Options B and C, "work in a garage" and "slip and fall", have no connection with corruption or payments. Therefore, option D is the exact match.

Verification / Alternative check:
If you check an idiom dictionary or reliable language resource, "grease someone's palm" will be defined as "to give someone money as a bribe" or "to pay someone unofficially to get something done". Example sentences often involve government offices, contracts, or services that are speeded up after payment. This confirms that "bribe" is the correct choice.

Why Other Options Are Wrong:
Option A, "dirty one's hands", suggests becoming involved in wrong or immoral activities but does not specify the act of giving money as a bribe. Option B, "work in a garage", interprets "grease" literally as oil used in mechanical work, which ignores the idiomatic sense. Option C, "slip and fall", refers to losing balance and is completely unrelated. Only option D, "bribe", accurately captures the meaning of the idiom.

Common Pitfalls:
Students sometimes over interpret idioms like "dirty one's hands" and think they are the same as "grease the palm", but exam setters usually look for the closest and most specific match. Another pitfall is taking the idiom literally, imagining real grease and physical work. To avoid confusion, remember that "palm" here symbolises the hand in which money is placed, and "greasing" refers metaphorically to making things move smoothly through payment.

Final Answer:
The idiom "grease the palm" means to bribe someone by giving money for an unfair favour.