Let , then

Given:

To find: the relation between f(xy) and f(x).f(y)

Explanation: First we will find f(xy), for this we will replace x with xy in the given equation , we get

Now we will find f(y), for this we will replace x with y in the given equation , we get

Using this we will find the value for f(x).f(y), we get

Comparing equation (i) and (ii), we get

⇒ f(xy)≤ f(x)f(y)

So, the correct answer is option (C)