Answer:
B. 2
Step-by-step explanation:
1) all the perpendicular lines are: y=x+C, where C - number;
2) in order to calculate C: to substitute (2;4) into the equation y=x+C:
4=2+C; ⇒ C=2;
3) finally, the required equation is: y=x+2.
The answer is B. 2.
