In which direction does a d-isomer rotate the plane of plane polarised light?

Explanation

**Step-by-Step Solution:**

1. **Understanding Polarized Light**: Plane polarized light consists of waves that vibrate in a single plane. When this light passes through a substance, it can be rotated depending on the optical activity of the substance.

2. **Identifying D-Isomers**: D-isomers refer to a specific configuration of chiral molecules. In organic chemistry, the "D" designation typically indicates that the molecule has a specific spatial arrangement of its atoms.

3. **Optical Activity of D-Isomers**: Chiral compounds can rotate the plane of polarized light. The direction of this rotation can be either clockwise (dextrorotatory) or counterclockwise (levorotatory).

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