Mark the letter A, B, C, or D to complete each of the given sentences.
1. My grandparents looked ______ my brother when he was small.
A. with B. at C. into D. after
2. A group of students carried ______ research on Korean culture and cuisine.
A. for B. out C. off D. by
3. We need to work ______ the high unemployment in our town.
A. out B. about C. for D. up
4. My friends were looking ______ information about Steve Jobs on the Internet.
A. on B. from C. for D. by