JEE Math Practice Question

Let $$f:\left( {0,\infty } \right) \to \left( {0,\infty } \right)$$ be a differentiable function such that f(1) = e and $$\mathop {\lim }\limits_{t \to x} {{{t^2}{f^2}(x) - {x^2}{f^2}(t)} \over {t - x}} = 0$$. If f(x) = 1, then x is equal to :

1. A.$${1 \over e}$$
2. B.e
3. C.$${1 \over 2e}$$
4. D.2e