The first thing to do here is to integrate the ordinary differential equation dy/dx = 1/x. This is equal to y = ln x + C. Assuming C is zero. y = lnx. substituting the two interval,
y1 = 0 y2 = ln 4
the rate of change then is equal to (ln4 - 0) / (4-1) equal to 2/3 ln 2. Answer is C
