In Speaking with an Older Person, Which Question Is Likely

In speaking with an older person, which question is likely to elicit the most accurate information about the individual's adherence to the medication plan?

A) "You take digoxin (Lanoxin) at the correct time, don't you?"
B) "Why didn't you take all of your digoxin (Lanoxin) last month?"
C) "How many doses of digoxin (Lanoxin) do you think you missed?"
D) "You have never missed a dose of digoxin (Lanoxin) , have you?"