Answer is (c) 3
Explanation :
The given curve is
y = (c1 + c2) cos(x + c3) – c4ex + c5
y = (c1 + c2) cos(x + c3) – c4ec5 .ex
y = A cos(x + c3) – B.ex
Since the given curve has 3 arbitrary constants, so, the order of the differential equation represented by the given curve is 3.