What theme is best revealed by this conflict?

One must mourn before moving on.

Explanation:

"No ship made sail next day until some shipmate had raised a cry, three times, for each poor ghost unfleshed by the Cicones on that field."

This sentence describes the grief, mourning, and respect the soldiers had for their lost comrades and amplifies the fact that the mourning must take place before moving on.  "No ship made sail next day until some shipmate had raised a cry..."

Cheers.

ok if it wasn't the hans one it was probably c or he thought the mountain was collapsing on them.

i may be wrong but i think your answer is flashback