第1775题：LIMITS OF FUNCTIONS

Let's look at a function $f$ that is 0 almost everywhere except for $\dfrac{1}{n}$  points, which lie on the line $y=x$ .

Part of the graph of $f$ looks something like this:

Now, what is the limit of $f(x)$ as $x$ approaches $\dfrac{3}{7}$ ?

A. The limit does not exist.

B. $\dfrac{3}{7}$

C. $\dfrac{1}{2}$

D. $0$

There is a TIP for this question.

From www.brilliant.org.