Which statement about electronic sources of job leads is the most accurate?

Which statement about electronic sources of job leads is the most accurate?
 
  a) Job banks and on-line services provide the potential of attracting hundreds of employers who are at a long distance from the job-seeker.
  b) Entering a resume into a database is the most expensive job search method available to job-seekers.
  c) The larger the company, the less likely it is to use resume database services to find job applicants.
  d) Job seekers who use electronic sources of job leads are spared from using other sources of job leads.