求问一道语法题

livebelieve

The success of the program to eradicate smallpox has stimulated experts to pursue what they had not previously considered possible--better control, if not eradication, of the other infections such as measles and yaws.

• Awhat they had not previously considered possible--better control, if not eradication, of the other infections such as  分析A选项
• Bwhat they had not previously considered a possibility--better control, if not eradication, of such infections like  分析B选项
• Csomething they had not previously considered possible-better control, if not eradication, of such infections as  分析C选项
• Dsomething not considered a previous possibility--better control and perhaps eradication, of other infections such as  分析D选项
• Ethe possibility of what they had not previously considered--better control and possibly eradication of infections like  分析E选项
  

选C  实在搞不懂if not eradication
题干是什么意思
control和something并列吗？？？、