4.The train ads were placed among family-oriented TV programs involving nature and America because ________.
A) they could focus on meaningful travel experiences
B) they could increase the effectiveness of the TV programs
C) their profits could be increased by some 15 percent
D) most travel-lovers and nervous fliers were believed to be among the audiences
出自:河南师范大学-小学教育(本科)-大学英语Ⅱ