The question requires selecting the most appropriate word to fill blank number 3 in the provided passage. The sentence describes an attack by Spitz on Buck: "He sprang upon Buck, and twice his teeth sank into his (3) ________ foe and ripped and tore the flesh to the bone."

Analyzing Blank (3) Context

We need a word that describes Buck, the 'foe', from Spitz's perspective during the attack. Let's examine the options:

• unresisting: This implies Buck was unable to fight back effectively at that moment.
• unsatiable: This means unable to be satisfied, usually related to hunger or desire.
• undetermined: This means not yet decided or known.
• unquenchable: This means unable to be extinguished or satisfied, often related to thirst or desire.

Selecting the Best Fit Word

The context describes Spitz violently attacking Buck, sinking his teeth and tearing flesh. In such a fierce attack, Buck might be momentarily overwhelmed or unable to offer strong resistance. Therefore, "unresisting" best describes Buck's state as Spitz's teeth sank into him. The words "unsatiable", "undetermined", and "unquenchable" do not logically fit the description of a physical foe being attacked.

The correct choice for blank (3) is unresisting, as it accurately reflects the victim's condition during a physical assault described in the passage.

Correct Option: A. unresisting