Arrange the types of arrangement in terms of decreasing packing efficiency.

Options

A. BCC `gt` Simple cubic `gt` CCP
B. `HCP gt C CP gt BCC`
C. `HCP gt B C C gt` Simple cubic
D. `C CP gt BC C gt HCP`

Explanation

To arrange the types of arrangement in terms of decreasing packing efficiency, we need to analyze the packing efficiencies of different crystal structures. Here’s a step-by-step solution:

### Step 1: Identify the Types of Arrangement
The types of arrangements we need to consider are:
- Simple Cubic (SC)
- Body-Centered Cubic (BCC)
- Hexagonal Close Packing (HCP)
- Cubic Close Packing (CCP)

### Step 2: Determine the Packing Efficiency of Each Arrangement
Next, we need to know the packing efficiency for each of these arrangements:
- **HCP and CCP**: Both have a packing efficiency of **74%**.
- **BCC**: Has a packing efficiency of **68%**.
- **Simple Cubic (SC)**: Has a packing efficiency of **54%**.

### Step 3: Arrange in Decreasing Order
Now that we have the packing efficiencies, we can arrange them in decreasing order:
1. HCP and CCP (74%)
2. BCC (68%)
3. Simple Cubic (54%)

### Final Arrangement
Thus, the final arrangement in terms of decreasing packing efficiency is:
- HCP / CCP (highest)
- BCC
- Simple Cubic (lowest)

### Conclusion
The correct order of packing efficiency from highest to lowest is:
**HCP = CCP > BCC > Simple Cubic**