Some great insights have already been shared, and I just want to add one more perspective regarding the three sub-question format that appears in many DI questions.
If you observe closely, you’ll notice a pattern in difficulty across the sub-questions. It is rare to see all three parts being equally hard, whether in terms of understanding, time consumption, or mapping to the data. In most cases, only one of the sub-questions is noticeably tougher, and that often becomes the deciding factor in whether you get the entire question right.
From the test-maker's perspective, each question still needs to be solvable within roughly two minutes. If all three sub-questions were difficult, that would make the entire set unrealistic to complete in time. So there is usually some balance built into the structure.
Your strategy should not be to give equal time to each sub-question. Instead, try to solve the easier ones quickly, and focus on identifying which part might require the most time. Ask yourself whether you can realistically solve the harder one within the remaining time or if it makes more sense to guess quickly and move on to the next. In many cases, your overall accuracy and score will improve by focusing your energy where it gives the best return.