Step 1: Understanding the Concept:
This question asks to identify the source poem of the given lines.
Step 2: Detailed Explanation:
These lines are from D. H. Lawrence's poem, "Snake". They describe the snake at the speaker's water-trough. After drinking its fill of water, the snake slowly lifts its head. The speaker observes this movement with fascination, describing it with the simile "as one who has drunken". This captures the slow, languid, and almost otherworldly quality of the snake's movement.
Step 3: Final Answer:
The quote describing the drinking animal is from the poem "Snake". Therefore, option (A) is the correct answer.