For each of the following, state whether the expense is discretionary, non-discretionary fixed, or non-discretionary variable. a) Karl has a bill for $120 for fixing the water heater. b) Freida pays $41.90 per month for house insurance. c) Sahid has just purchased a new home theatre television and will make monthly payments of $75 to the electronics store. d) Karen's rent is $1200 per month. e) Carol's phone bill for July is $72.53. f) Lynn paid $135.75 in plumbing repairs last month. g) Robert purchased a new video game system for $499.99.