If corporations want to improve response rates, then they need to be more carefully target the individual to whom they mail advertising, thereby cutting down ...
原来的reasoning有个漏洞(也是GMAC考察我们细心和逻辑缜密之处),即很多种forms of advertising都有一定的response rates。If corporations want to improve response rates, then they need to identify which form of advertising they want to use.