Which of the following is not a unit of time

Options

A. second
B. minute
C. hour
D. light year

Answer

To solve the question of which of the following is not a unit of time, we will analyze each option provided.

### Step 1: Identify the options
Let's assume the options given are:
- A) Second
- B) Minute
- C) Hour
- D) Light Year

### Step 2: Analyze each option
1. **Second**:
- The second is the SI unit of time. It is widely used to measure time intervals.
- Conclusion: This is a unit of time.

2. **Minute**:
- A minute is equal to 60 seconds. It is also a commonly used unit of time.
- Conclusion: This is a unit of time.

3. **Hour**:
- An hour is equal to 60 minutes or 3600 seconds. It is another standard unit of time.
- Conclusion: This is a unit of time.

4. **Light Year**:
- A light year is defined as the distance that light travels in one year. It is approximately equal to 9.46 x 10^15 meters.
- Conclusion: This is a unit of distance, not time.

### Step 3: Determine the answer
Based on the analysis, the option that is not a unit of time is **D) Light Year**.

### Final Answer:
**D) Light Year** is not a unit of time.

---