This problem seems badly worded and/or vague.
It looks like you plugged x = 3 into the inverse [tex]f^{-1}(x)[/tex] function to get 3 as the output, which is correct.
However it seems like your teacher wants you to find the (x,y) point on f(x). This means s/he is asking "what x value will get us y = 10?" As you found through working with the inverse, the x value x = 3 does that.
We can see it as such
f(x) = 3x+1
f(3) = 3*3+1
f(3) = 10
So in a sense, you were working backwards.
The point (3,10) is on the graph of f(x)
While the point (10,3) is on the graph of [tex]f^{-1}(x)[/tex]
It's likely your teacher wants you to select choice C
