# Mensa Romania IQ test question - diagonal, vertical, horizontal lines combined

• Welcome to Puzzling! I see you've credited Mensa Romania - could you provide a link or other sourcing information? Dec 17 '20 at 3:54
• "I think it's B, but why?" Only you know why you think it's B. Dec 17 '20 at 6:16

E

because

The third column shows the lines that are different between the first two columns. That is, if a line segment appears in both the first two columns, then it will not appear in the third; likewise if a line segment appears in neither of the first two columns it will not appear in the third. However any line segment that appears in exactly one of the first two columns will be present in the third column.
In a computer-science context, you might say that the columns are related by exclusive-or (XOR) - applying that operation to any two columns will yield the other.

• And the same is true for rows. Dec 17 '20 at 6:15
• Good point - once I saw the pattern I mentioned, I stopped looking
– lxop
Dec 17 '20 at 19:55

Letter E-) When LINE appears in 2 figures It Works as an erase. You should erase the LINE repeated and maintain singles ones.