It could tell them data of how many days the student was absent or how many days the student was present.
"Like sparks from a blacksmith's window" refers to the sparks that happen when a blacksmith is working. The meaning depends on the context. The context should usually be something like anger, exploding anger, or it could be excitement...
In this text, you are informed on what the term "Sandwich generation" means. You are then provided an example (2nd sentence). The example can be found when the transition word <em>for instance</em> is used. From this information, you should be able to conclude that the correct answer is a. definition and example.
