Professor Tromborg would like to purchase new speakers. Unfortunately, he lives with a cat (F. catus) who insists on using his speakers for scratching posts. Interestingly, during its kittenhood, this cat was raised in an environment devoid of all visual stimuli except horizontal stripes. Consequently, if professor Tromborg wishes to purchase speakers which his rotten cat will have difficulty seeing, he should not __________:
a. obtain speakers with horizontally striped grillecloths.
b. obtain speakers with vertically striped grillecloths.
c. obtain speakers with polka-dot grillecloths.
d. get a groundsquirrel.