Directions: In the following questions, choose the best answer from the five choices listed.

An operation, *, is defined as follows: for any positive numbers a and b. Which of the following is an integer（）

A. 3
B. 6
C. 8
D. 10
E. 12

A. In 1991, adults whose highest degree was at least a bachelor’s degree were more than twice as likely to participate in adult educa-tion than those whose highest educational attainment was a high school diploma or GED (high school equivalency diploma..
B. On a percentage basis, from 1991 to 1995, the greatest increase in the adult education par-ticipation rate was among those adults whose highest educational attainment was grades 9-12, without earning a high school diploma.
C. In 1995, more people participated in adult edu-cation programs than in 1991.
D. From 1991 to !995 the rate of participation in adult education among the groups represented in the graphs increased the least for those who had attained at least a bachelor’s degree.
E. In 1995, more adults with at least a bachelor’s degree participated in adult education than did adults who attended some college but did not earn a college degree.