Mom and Dad think it is real funny, and laugh when their 2-year-old, Bruce, says dirty words. When Bruce is sent home from kindergarten because of swearing, they don't understand why he cusses

Now when he cusses at home they ignore the cussing (they don't think it's cute anymore). Laughing in this example is:
a. positive reinforcer.
b. a negative reinforcer.
c. a primary reinforcer.
d. a neutral stimulus.

Answer a % correct 68 a= 68 b= 23 c= 9 d= 0 r = .36