In an xy-coordinate plane, a line is defined by y = kx + 1. If (4, b), (a, 5), and (a, b+1) are three points on the line, where a and b are unknown, then k = ?  Options.
A) 1/2	B) 1	C) 3/4	D) 2	E) 5/2
b=4k+1...(1)   b+1=ak+1...(2)   5=ak+1...(3)   Taking (2) and (3)   5=b+1   b=4   Taking (1)   4=4k+1   k=3/4   Answer :3/4
<result>C</result>
In an xy-coordinate plane, a line is defined by y = kx + 1. If (4, b), (a, 5), and (a, b+1) are three points on the line, where a and b are unknown, then k = ?