(A): ABAB ..... pattern of close packing gives hcp arrangement
(R): In hcp arrangement each sphere is associated with two tetrahedral voids 

Options

A. Both (A) and (R) are true. (R) properly explain (A)
B. Both (A) and (R) are true. (R) does not explain (A)
C. (A) is true. (R) is false
D. (A) is false. (R) is true

Answer

To solve the question, we need to analyze both the assertion (A) and the reason (R) provided in the context of the close packing arrangements in solids.

### Step-by-Step Solution:

1. **Understanding Assertion (A)**:
- The assertion states that the ABAB pattern of close packing gives a hexagonal close packing (hcp) arrangement.
- In hcp, the spheres are arranged in layers where the second layer fits into the depressions of the first layer, and the third layer fits back into the depressions of the second layer, repeating this pattern.

2. **Understanding Reason (R)**:
- The reason states that in the hcp arrangement, each sphere is associated with two tetrahedral voids.
- In a close-packed structure, voids are created between the spheres. In hcp, each sphere does indeed have tetrahedral voids associated with it.

3. **Analyzing the Relationship**:
- The assertion is true because the ABAB pattern indeed corresponds to the hcp arrangement.
- The reason is also true because in hcp, each sphere is associated with two tetrahedral voids.

4. **Determining the Explanation**:
- While both the assertion and reason are true, the reason does not explain the assertion. The assertion is about the packing arrangement, while the reason discusses the voids associated with the spheres in that arrangement.

5. **Conclusion**:
- Since both A and R are true, but R does not explain A, the correct option would be that both statements are true, but R does not explain A.

### Final Answer:
Both A and R are true, but R does not explain A.