Which sentence is an example of direct characterization?

jake and sam shouldered the next pair of fifty-pound food packs and began another long trudge up the hill.

"oh, this is just swell," jake said, covering his ears to block out the sound.

jake had a short fuse when he was under stress, and this entire adventure was not bringing out the best side of his personality.

of course, staking a claim and striking it enormously rich on klondike gold had seemed like a wonderful idea last summer.