STEP - BY - STEP EXPLANATION
What to find?
Equation of a straight line.
Given:
Points; (4, 5) and (5,6)
Step 1
Identify its coordinate.
x₁= 4 y₁=5
x₂=5 y₂=6
Step 2
Determine the slope (m) using the formula below:

Step 3
Find the intercept(c) using the formula below:

Step 4
Form the equation by substituting m=1 and c=1 into the general equation.

ANSWER
A. y=x+1