A select query that calculates a sum, an average, or a similar statistic, and then groups the results by two sets of values

In which of the following circumstances does an individual not have a reasonable expectation of privacy?

A. Placing a telephone call on your cell phone B. Sending a letter through the US mail C. Sending an email at work D. Retrieving your personal voicemail

What is the difference between a local variable and an instance variable?

What will be an ideal response?