Answer:
modify his website and improve his SEO to target those search engines
Explanation:
Based on this information it can be said that, since Jeff knows that he has a large customer population through Google and Bing's search engines then he needs to modify his website and improve his SEO to target those search engines. SEO stands for Search Engine Optimization and is the process of implementing the correct keywords and information in order to appear more often on search engines. This will largely increase the number of individuals that see Jeff's website when searching on Google or Bing.