1) Select all of that following that are best described as sunk costs
a. The time spent developing a relationship with your significant other.
b. The morning run that I miss out on so that I have time to go to Starbucks before class.
c. The cost of an expensive pair of shoes that my girlfriend wants, but will likely never wear.
d. The deposit made a month ago to hold your spot on a rafting trip.
e. The additional money you must pay if you actually go on the rafting trip.
f. The new bike you could buy with the total amount of money you will spend on the rafting trip.