Not sure how you define "di-ionic." If you mean it is charge neutral, i.e., the Na+ and SO3- balance each other, then can you give an example where that is not the case? In other words, it becomes a silly question, as distractors (a) and (b) are impossible. I don't think that is the case, though.
My guess, based on the other options present and the above observation, is that as a surfactant, it would be classified as answer (b), anionic.
The structure shown is wrong, as succinic acid is a 4-carbon dicarboxylic acid. Malonic acid has only 3 carbons. If it is intended as malonic acid, then the name is wrong and that central carbon is very acidic. I would certainly confirm that structure before committing to anything.
If on the other hand, the author of that link simply forgot the other CH2, s/he deserves chiding. The correct answer then becomes none, because the root question has a fatal flaw. The best of the given choices is still (b), based on the name.
John
Edit: Wikipedia calls it an anionic detergent, which confirms my guess on the naming convention. A di-ionic surfactant would be something with two ionic groups on the main, active portion. I am not sure whether the ionic groups need to be that same, like a di-or more likely bis-quaternary surfactant, or whether they can be of opposite charge, as in a zwitterion.
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