Seth owns 150 shares of stock with a basis of $1800 at $12 per share. The stock splits three for one. How many shares does he now own, and what is his basis per share?

a) 50 shares with a basis of $36 per share

b) 50 shares with a basis of $108 per share

c) 450 shares with a basis of $4 per share

d) 450 shares with a basis of $12 per share