Percentage increase is calculated using the formula 100(b-a)/a%, where b is the figure for 2007 and a the figure for 1997. When a=0 (as it is for Davao) we are dividing by zero which gives us an indefinite answer (usually represented by infinity), so on this basis we do one of two things: we ignore the data as being inestimable, or we say that this is the greatest increase. Apply the formula to each case:
Cagayan Valley: 160%,
Car: 200%,
Mimaropa: 200%,
Caraga: 100%,
Davao: infinite percentage (indefinite)
Zamboanga: 0%
In order greatest to least to greatest: Davao, (Car, Mimaropa), Cagayan Valley, Caraga, Zamboanga. When we look at the answer choices, Davao is never in a leading position, so it’s not considered amongst the highest, because the percentage increase cannot be calculated. We conclude that we ignore this because the percentage cannot be determined. So that leaves Car and Mimaropa as the leaders (200%) with Cagayan Valley (160%) following.
The given answers don’t have Car and Mimaropa as the sole leaders. Let’s look at the answer choices.
Not a, because, although Cagayan Valley has the greatest absolute difference, it is not the highest percentage increase.
Not b, because Caraga has a lower percentage increase than Cagayan Valley.
Possibly c, because only Zamboanga (which has no increase) is excluded.
Not d, because Cagayan Valley has been omitted and it has a higher percentage increase than Caraga.
Not e, because Zamboanga has no increase.
Out of these I would pick c.