GDP increases by $1000. Which of the following transactions is responsible? a. Monika gives her boyfriend her motorcycle, which she purchased for $1000 a year ago. b. Jack sells his motorcycle to a friend for $1000. c. Karens motorcycle, for which she paid $1000 two years ago, is stolen from her parking place. d. Lena pays a motorcycle shop $1000 to repair and overhaul her motorcycle.