The mixed salt among the following is :

Options

A. `CaOCl_(2) `
B. `NaKSO_(4)`
C. `Mg(OH)Cl `
D. All

Explanation

To determine which of the given options is a mixed salt, we need to identify the presence of two different types of cations or anions in each option. A mixed salt contains more than one type of cation or anion.

Let's analyze each option step by step:

1. **Option 1: CaOCl2**
- This salt contains the ions: Ca²⁺, O²⁻, and Cl⁻.
- Here, we have one cation (Ca²⁺) and two different anions (O²⁻ and Cl⁻).
- Since there are two types of anions, this qualifies as a mixed salt.

2. **Option 2: NaKSO4**
- This salt contains the ions: Na⁺, K⁺, and SO₄²⁻.
- Here, we have two different cations (Na⁺ and K⁺) and one anion (SO₄²⁻).
- Since there are two types of cations, this also qualifies as a mixed salt.

3. **Option 3: Mg(OH)Cl**
- This salt contains the ions: Mg²⁺, OH⁻, and Cl⁻.
- Here, we have one cation (Mg²⁺) and two different anions (OH⁻ and Cl⁻).
- Since there are two types of anions, this also qualifies as a mixed salt.

After analyzing all the options, we find that all three options contain mixed salts. Therefore, the answer is that all the given options are mixed salts.

### Final Answer:
All the options provided are mixed salts.