Lenski and Travisano compared what happened to the fitness of cells in 12 replicate lines of E. ...

Lenski and Travisano compared what happened to the fitness of cells in 12 replicate lines of E. coli. The re-sults of the experiment graphed in the figure above indicate that:
 
  a. only 500 generations into the experiment, natural selection had already increased the fitness of the evolved strains.
  b. the average fitness decreased substantially over the first 2,000 to 3,000 generations of the ex-periment.
  c. the average fitness increased substantially over the first 2,000 to 3,000 generations of the ex-periment.
  d. A and B.
  e. A and C.