 Shares of Dollar Tree Inc. DLTR, 1.15 dropped 3.2 in premarket trading Tuesday, after the discount retailer reported fiscal third-quarter earnings that rose above expectations, but said full-year profit would be at the low-end of guidance as strong consumable sales pressure margins. Net income rose to 266.9 million, or 1.20 a share, from 216.8 million, or 96 cents a share, in the year-ago period. 