People are crowding around _______ pit into which _______ elephant has fallen. I have never seen elephant looking more bewildered _______ miserable. Here it is in a most undignified position, thrust into a pit and made to look up _______ a vast curiosity-stricken crowd.

The correct option is: a, an, and, at.

Let's break down the passage and analyze the requirement for each blank step-by-step:
1. First blank (a): "People are crowding around a pit..."
The word "pit" is a singular, countable noun starting with a consonant sound (/p/). Since it refers to a non-specific pit that is being introduced in the sentence, we use the indefinite article "a".
2. Second blank (an): "...into which an elephant has fallen."
The word "elephant" is a singular, countable noun starting with a vowel sound (/e/). Therefore, the correct indefinite article to precede it is "an".
3. Third blank (and): "I have never seen elephant looking more bewildered and miserable."
Here, the sentence describes two parallel states of the elephant using the adjectives "bewildered" and "miserable". The coordinating conjunction "and" is the appropriate connector to link these two descriptive terms.
4. Fourth blank (at): "...made to look up at a vast curiosity-stricken crowd."
The preposition "at" is used here to follow the verb phrase "look up" and indicate the direction or target of the elephant's gaze (the crowd).

Combining these, the complete, grammatically correct passage reads:
"People are crowding around a pit into which an elephant has fallen. I have never seen elephant looking more bewildered and miserable. Here it is in a most undignified position, thrust into a pit and made to look up at a vast curiosity-stricken crowd."