Which function goes with this graph?

From the given points on the graph we can find which function represents this graph.

A point on the graph is (3, 1). This means if we substitute x = 3 the answer must be 1.

The property of log is that 

This suggests, if the base of log is equal to the number for which we are finding the log, the answer must be 1.

So, in this case we have:



Since the answer is 1, the base of log must be 3.

In the given options, only option 3rd is with base 3.

So, the correct answer is option 3.