From the given examples, we observe the following pattern:
- For 'ACID' = 1C3D: Replace 'A' with '1', 'C' with 'C', 'I' with '3', and 'D' with 'D'.
- For 'PAMPER' = P1MP2R: Replace 'A' with '1', 'P' remains 'P', 'M' remains 'M', 'P' remains 'P', 'E' with '2', and 'R' remains 'R'.
- For 'BOMBAY' = B4MB1Y: Replace 'O' with '4', 'M' remains 'M', 'B' remains 'B', 'A' with '1', 'Y' remains 'Y'.
Now applying the same pattern to 'UNIVERSITY':
- 'U' remains 'U'.
- 'N' remains 'N'.
- 'I' is replaced by '3'.
- 'V' remains 'V'.
- 'E' is replaced by '2'.
- 'R' remains 'R'.
- 'S' remains 'S'.
- 'I' is replaced by '3'.
- 'T' remains 'T'.
- 'Y' remains 'Y'.
Thus, 'UNIVERSITY' is coded as "5N3V2RS3TY".
Therefore, the correct answer is \( \boxed{3} \).