Sure, it's about looking at things logically and seeing what information you have available. So there are 106 people total, but if we add up each category the total is 126. In other words, some people fall into more than one category and so have been counted more than once. basically, there are 20 "extras" that are a result of people either being in two or three categories. Q18 tells us that there are three people in three categories, so they account for 9 rather than 3.
Now there are probably other ways to go about solving it, but algebraically:
Let N=the number of people in one category
Let X=the number of people in two categories
N+2X+9=126
X's count for two, three people counted thrice = 9, all good?
we also have N+X+3=106 since they must add up to the number of participants
If we minus the top from the bottom we get: X+6=20 and X=14
So N=89
However, having spent 10 minutes doing this I just realised some people could be in none of the categories, i.e. born abroad, under 1.6m and right handed so the answer should be E....