Final answer:
The question requires the identification of digits represented by letters, with four specific numbers as options. Each option is a combination of the digits 0, 1, 8, and 9, and the task is to determine which combination is correct.
Step-by-step explanation:
The question involves understanding which digits are represented by four letters. Each letter represents a different digit from the set {0, 1, 8, 9}. The options given in the question are different numbers that combine these digits: a) 1889, b) 1980, c) 8091, d) 9180. To determine which option correctly represents the digits, we should look for any patterns or rules that could apply to the number formation listed in the options that align with the digits provided.