The correct order of pseudohalide , polyhalide and interhalogen are :
(A)`BrI_2^-,OCN^(-),IF_5` , (B)`IF_5,BrI_2^-,OCN^(-)` , ( C)`OCN^(-),IF_5,BrI_2^(-)` , (D)`OCN^(-),BrI_2^(-),IF_5`

Explanation

To solve the question regarding the correct order of pseudohalide, polyhalide, and interhalogen compounds, we need to identify the classification of each compound provided in the options. The compounds given are OCN^(-), BrI_2^(-), and IF_5.

### Step 1: Identify the Types of Compounds
- **Pseudohalide**: Compounds that behave like halides but are not halogens. In this case, OCN^(-) (cyanate ion) is a pseudohalide.
- **Polyhalide**: Compounds formed by the combination of halogens. BrI_2^(-) (bromine diiodide ion) is a polyhalide.
- **Interhalogen**: Compounds formed from two different halogens. IF_5 (iodine pentafluoride) is an interhalogen.

### Step 2: Classify Each Compound
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