Choose the option that best expresses the meaning of the idiom "to bite the bullet".

Introduction / Context:
The idiom "to bite the bullet" is commonly used in modern English, including newspapers, films, and everyday speech. The phrase has a historical background, but in present usage it has a stable figurative meaning. This question checks whether you know that idiomatic meaning, rather than guessing from the literal image of a bullet.

Given Data / Assumptions:

• Idiom: "to bite the bullet".
• Options describe different kinds of difficult or serious situations.
• Only one option corresponds to the standard figurative sense that native speakers use.

Concept / Approach:
Historically, the phrase is often explained by the idea that soldiers or patients would literally bite on a bullet during painful medical procedures when no anaesthetic was available, so that they could endure the pain. In modern English, the idiom has shifted to mean forcing oneself to do something unpleasant or difficult, especially after having delayed it.

Step-by-Step Solution:
Step 1: Recall the established meaning: "to bite the bullet" means to finally accept and face a difficult or unpleasant task that you have been avoiding. Step 2: Examine option B: "To do something difficult that one has been hesitating over." This directly matches the idea of finally facing an unpleasant duty. Step 3: Look at option A: "Hatred should be nipped in the bud." This is a moral statement, not connected to the idiom. Step 4: Consider option C: "To punish someone who was later found to be not guilty." This refers to wrongful punishment and has no link to the idiom. Step 5: Evaluate option D: "To prevent someone form getting killed." This talks about saving a life, which is again unrelated. Step 6: By elimination and by meaning, option B is clearly correct.

Verification / Alternative check:
Think of typical usage: "I hate going to the dentist, but I will have to bite the bullet and make an appointment." Here, the speaker is forcing themselves to do something they dislike but cannot avoid. None of the other options fits well into such a sentence, while option B fits perfectly: it is a difficult task one has been hesitating over.

Why Other Options Are Wrong:

• Option A: Explains a different proverb about stopping bad emotions early, not about facing difficulty.
• Option C: Describes a miscarriage of justice, which is very specific and does not match the idiom's sense.
• Option D: Involves rescuing someone, not accepting a tough personal duty.

Common Pitfalls:
Some learners are misled by the presence of the word "bullet" and assume the idiom must involve killing or preventing death. Others confuse it with phrases like "take the bullet" or "dodge a bullet". The safest approach is to remember that idioms often have meanings shifted far away from literal word pictures, so memorising them through repeated reading is helpful.

Final Answer:
"To bite the bullet" means to do something difficult that one has been hesitating over.