Option B.
Step-by-step explanation:
The given function is
![y=3x-1](/tpl/images/0273/3552/44d6f.png)
We need to find the value of the function when x=-1.
Substitute x=-1 in the given function.
![y=3(-1)-1](/tpl/images/0273/3552/c8c63.png)
On simplification we get
![y=-3-1](/tpl/images/0273/3552/369e3.png)
![y=-4](/tpl/images/0273/3552/a0bc1.png)
The value of the function y=3x−1 is -4 at x=−1.
Therefore, the correct option is B.