1: d Is correct. The verb here is "to call," and the sentence is talking about the future.
2. c is correct. "Take a drink in case you get thirsty." While a little awkward, it's still grammatically correct this way.
3. d is correct. Again, "to take" is the verb. This, however, is less an "in the future" kind of thing, but rather, an "in general" kind of thing. As in, take care of your health at all times! :)
4. b is correct. The use of like makes this what we call a simile. You can tell a simile by the use of the words "like" or "as." They compare two things together, sometimes in ways that aren't literal, such as above. He swims like a fish, but he isn't a fish.
And this doesn't necessarily have anything to do with these sentences, but since we're on the subject of similes, metaphors do the exact same thing, only without the use of "like" or "as" in English. I'm sure you're probably familiar with the concept of metaphors, but an example of one would be, "She's a breath of fresh air." She isn't literally a breath of fresh air, but... the idea is that she is refreshing. I really hope I'm making sense... :)