To solve the problem, we need to determine the mode of the sequence \( A, B, C, D, \ldots, Z \).
1. Understanding the Sequence:
The sequence \( A, B, C, D, \ldots, Z \) consists of the 26 letters of the English alphabet in order. Each letter appears exactly once in the sequence.
2. Definition of Mode:
The mode of a data set is the value that appears most frequently. If no value repeats, then the data set has no mode.
3. Analyzing the Frequency:
In the given sequence, each letter (from \( A \) to \( Z \)) appears exactly once. Since no letter repeats, there is no value that occurs more frequently than any other.
4. Conclusion:
Since no letter in the sequence repeats, the sequence has no mode.
Final Answer:
The mode of the sequence \( A, B, C, D, \ldots, Z \) is \({\text{No mode}}\).