In the following question, a statement of assertion followed by a statement of reason is given. Choose the correct answer out of the following choices:

Assertion: Aqueous gold colloidal solution is red in colour.

Reason : The colour arises due to scattering of light by colloidal gold particles. .

Both assertion and reason are true and the reason is the correct explanation of the assertion.

Aqueous gold colloidal solution is red in colour. The colour is due to scattering. It depends upon the size of particles. Finest gold sol has red colour. As the size of the particle increases, it becomes purple and then blue and finally golden yellow.