Step 1: The question refers to the inner strength of the character in "The Sleeping Porter."
Step 2: The poem paints a picture of a man who is a "king" in his dreams, conquering natural and formidable obstacles.
Step 3: The poem describes the porter's resilience and courage. His work takes him through difficult and wild terrain. He is portrayed as someone who faces the harshness of nature head-on. Challenging the 'mountains' symbolizes his daily struggle against the immense, immovable burden of his work and the difficult landscape. The marked answer (A) wild animals also fits this theme of conquering nature, but 'mountains' better represents the scale of his daily challenge.