Which of the given example is not a type of silk?

The correct option is D China silk
Basically, silk is of two types:

$1.$ Mulberry silk

$2.$ Non-mulberry silk

Mulberry silk is again of two types:

$1.$ South silk

$2.$ Kangiwaram silk

Non-mulberry silk is again of so many types:

$\left(i\right)$ Tassar silk

$\left(ii\right)$ Eri silk

$\left(iii\right)$ Muga silk

$\left(iv\right)$ Anaphe silk

$\left(v\right)$ Fagara silk

$\left(vi\right)$ Coan silk

$\left(vii\right)$ Mussel silk

$\left(viii\right)$ Spider silk

So, china silk is not a type of silk.