Which of the following debt collector actions is legal?

a. Contacting you at inconvenient times (after 9:00 PM and before 8:00 AM)
b. Communicating with your employer about
c. the debt without your permission
d. Contacting you at work if you have informed them you are not allowed to take personal calls
e. Threaten to sue you (assuming they have the right and intent to do so)