Answer:
B)
Step-by-step explanation:
A function is when every input has one output.
Easiest way is to do the "vertical line test" and "horizonal line test."
Basically you draw a vertical line and a horizontal line.
If either line passes through more than one point, then it is not a function.
The only one that passes them is B, the line.
A. 6x-y=1 can go to 6x-y-1=0 and then 6x-1 = y