How many arrangements can you make in a five letter word using the letters from the word 'ARTICHOKESU' such that at least three vowels are always together? O a. 4! ((2) (2) + (3) (9) + (4) (9) O b. 5!x (()() + (A) (A) + (9) (9)) O c. 5! (() (2) + (4) (9) + (9) (9) ) O d. 4!x (() () + () (9) + (*) (9))