Choose the option that best explains the idiom "spin ones wheels" as used in everyday English.

Introduction / Context:
The idiom "spin ones wheels" comes from an image in which a vehicle tire spins in mud or snow without the vehicle moving forward. In figurative use, it describes situations where people are busy and active but make no real progress. This question requires you to identify the option that captures that sense of wasted effort and lack of results.

Given Data / Assumptions:

• Idiom: "spin ones wheels".
• Options describe different types of behaviour or activity.
• We assume the widely accepted modern meaning used in business, study, and personal contexts.

Concept / Approach:
Idiomatic interpretation focuses on outcome, not only on activity. "Spinning wheels" suggests motion without movement, effort without progress. Therefore, the correct paraphrase must include both a sense of exertion and the idea that the effort leads to little or no gain. Options that describe bragging, luck, or journeys do not include this crucial second part about lack of progress.

Step-by-Step Solution:
Step 1: Recall the core meaning of the idiom: to work hard or stay busy without achieving meaningful results.Step 2: Examine option (a): "Keep bragging about oneself." This is about boasting, not effort or progress, and does not fit the metaphor.Step 3: Examine option (b): "Try your luck." This describes taking a chance or attempting something uncertain; it does not imply wasted effort.Step 4: Examine option (c): "Expel much effort for little or no gain." This matches the idea of working hard but not moving forward, exactly like a tire spinning in place.Step 5: Examine option (d): "Start a long journey." This suggests the beginning of progress, which is the opposite of being stuck.Step 6: Conclude that option (c) correctly expresses the meaning of the idiom.

Verification / Alternative check:
Look at example sentences: "We keep spinning our wheels on this project and never reach a decision" or "If you study without a clear plan, you may just spin your wheels." In both cases, people are doing something, but results are missing. Replacing the idiom with option (c) gives: "We keep expending much effort for little or no gain on this project", which preserves the entire sense. The other options would distort the meaning by introducing bragging, luck, or journeys.

Why Other Options Are Wrong:

• Option (a): Relates to self-praise; it ignores the notion of wasted effort.
• Option (b): Focuses on chance and risk-taking rather than the repetitive, unproductive nature of the activity.
• Option (d): Implies progress and movement, which is the opposite of spinning in place.

Common Pitfalls:
Some test-takers may be distracted by the idea of wheels and think of travel, leading them to choose option (d). Others may vaguely associate "spinning" with "trying something out", leaning toward option (b). To avoid such traps, always break the idiom into image and outcome: the image of a wheel stuck in mud and the outcome of remaining in the same place despite effort. Only option (c) captures both aspects.

Final Answer:
The idiom "spin ones wheels" means to "expel much effort for little or no gain", so option (c) is correct.