Step 1: Fill the first two blanks with the correct indefinite articles.
The first blank comes right before "pit," which starts with the consonant sound /p/, so it takes "a": "a pit."
The second blank comes right before "elephant," which starts with the vowel sound /e/, so it takes "an": "an elephant."
This immediately rules out any option that does not start "a; an", which eliminates options (A), (C) and (D), leaving only option (B) to check further.
Step 2: Fill the third blank, joining two describing words.
The sentence reads "looking more bewildered ___ miserable," where "bewildered" and "miserable" are two adjectives describing the same elephant.
Two adjectives listed together like this need the joining word "and": "bewildered and miserable."
Step 3: Fill the fourth blank, completing the phrasal verb.
The phrase "made to look up ___ a vast, curiosity-stricken crowd" describes the elephant looking upward towards the people around the pit.
"Look up at" someone or something is the correct phrasal verb for looking upward towards them, so the blank takes "at": "look up at a vast ... crowd."
Step 4: Confirm the full sequence.
Putting all four words in place gives: "a pit into which an elephant has fallen ... bewildered and miserable ... look up at a vast, curiosity-stricken crowd," which is exactly the sequence "a; an; and; at."
Final Answer:
The correct sequence of words is "a; an; and; at," option (B). \[ \boxed{\text{Option (B): a; an; and; at}} \]