Kyle is potty training his 3-year-old daughter. She is supposed to let her father know whenever she needs to use the toilet, but she is having accidents (target behavior) more than actually using the toilet. Per the advice of his pediatrician, Kyle has decided to have his daughter wash her underwear after each accident (target behavior). His daughter starts to have fewer accidents. Kyle used _______ to condition his daughter's behavior.
a) Positive reinforcement
b) Negative reinforcement
c) Positive punishment
d) Negative punishment