The graph shows the number of public service announcements that a radio station played throughout the day. Public Service Announcements (PSAs) Aired

A graph has hours on the x-axis, and number of P S A's on the y-axis. A line goes through (1, 4) and (2, 8).

Which equation can be used to represent the number of public service announcements, y, in x hours?
y = StartFraction x Over 4 EndFraction
y = 4
y = 4 x
y = x + 4