Explanation
This is a problem of successive percentage change
So if there is a percentage change by a% and then by b%, the resultant % change is given by the formula-
Resultant % change = a + b + \(\frac{( a * b )}{100}\)
For Feb ;
Resultant % change = 10 % ---- (Given)
Till Mar ; (15% less)
Resultant % change = 10 + (-15) + \(\frac{(10 * (-15))}{100}\) = -6.5%
Similarly,
Till Apr ; (20% greater)
Resultant % change = -6.5 + 20 + \(\frac{((-6.5) * 20)}{100}\) = 13.5 - 1.3 ~ 12 %
Till May ; (10% less)
Resultant % change = 12 + (-10) + \(\frac{(12 * (-10))}{100}\) = 0.8 %
Till Jun ; (5% greater)
Resultant % change = 0.8 + 5 + \(\frac{(0.8 * 5)}{100}\) = 6.xx %
So , Least change is in May (0.8%) ... Ans : D