Reread this excerpt from The Call of the Wild. He did not like to be approached on his blind side. Of this offence Buck was unwittingly guilty, and the first knowledge he had of his indiscretion was when Sol-leks whirled upon him and slashed his shoulder to the bone for three inches up and down. Forever after Buck avoided his blind side, and to the last of their comradeship had no more trouble. His only apparent ambition, like Dave's, was to be left alone.

What is the best description of Sol-leks‘s character, based on this excerpt?

He is a brute of a dog who seeks opportunities to show his strength.
He does not seek confrontation, but he is vicious in his own defense.
He is a faithful friend who guards his teammates from violent attacks.
He is a loner, but he is receptive to Buck’s offering of friendship.