D. Free association is a type of therapy where the therapist encourages the client to talk about whatever comes to mind.
Answer:
a change from one day to the next day
Well really, it could not be both A and B, as option B contains the world 'Only' which means it can not (depending on the context) be put with other options, so that rules D out, low levels of second hand smoke can still be harmful, it is even listed on the National Cancer Institute