Name the labelled parts A, B, C and D in the diagram given below.
- Stigma (A): The sticky surface at the top of the pistil which receives pollen grains.
- Style (B): The stalk that connects the stigma to the ovary.
- Ovary (C): The enlarged basal portion that contains ovules.
- Ovule (D): The structure inside the ovary where fertilisation occurs and seeds develop.
In the given figure, \( PQ \) and \( PR \) are tangents to the circle such that \( PQ = 7 \, \text{cm} \) and \( \angle RPQ = 60^\circ \).
The length of chord QR is: