Which of the following represent the correct order of decreasing reactivity?

Options

A. `Mg gt Al gt Zn gt Fe`
B. `Mg gt Zn gt Al gt Fe`
C. `Al gt Zn gt Fe gt Mg`
D. `Mg gt Fe gt Zn gt Al`

Explanation

To determine the correct order of decreasing reactivity among metals, we can refer to the activity series of metals. The activity series lists metals in order of their reactivity, with the most reactive metals at the top and the least reactive at the bottom.

### Step-by-Step Solution:

1. **Understand the Activity Series**: The activity series is a list that ranks metals based on their reactivity. The higher a metal is on the list, the more reactive it is.

2. **Identify the Metals**: In this case, we need to focus on the metals mentioned in the question. Let's consider magnesium (Mg), aluminum (Al), zinc (Zn), and iron (Fe).

3. **Refer to the Activity Series**: Based on the activity series, the order of reactivity for the mentioned metals is as follows:
- Magnesium (Mg) - Most reactive
- Aluminum (Al)
- Zinc (Zn)
- Iron (Fe) - Least reactive

4. **Write the Order of Decreasing Reactivity**: From the above information, we can write the order of decreasing reactivity:
- **Mg > Al > Zn > Fe**

5. **Conclusion**: Therefore, the correct order of decreasing reactivity among the metals mentioned is Magnesium, Aluminum, Zinc, and Iron.

### Final Answer:
The correct order of decreasing reactivity is: **Mg > Al > Zn > Fe**