Which statement accurately reflects Mohamed and Fritsvold's statements in their article Damn, It ...

Which statement accurately reflects Mohamed and Fritsvold's statements in their article
  Damn, It Feels Good to be a Gangsta about marijuana use and marijuana sales?
 
  a. Using marijuana is a gateway to using harsher drugs; however, selling marijuana is not a
  gateway to selling harsher drugs.
  b. Using and selling marijuana is a gateway to using and selling harsher drugs.
  c. Using and selling marijuana is not a gateway to using and selling harsher drugs.
  d. Using marijuana is not a gateway to selling harsher drugs; however, selling marijuana is
  a
  gateway to selling harsher drugs.