The last day of a century cannot be

Answer:

The last day of a century cannot be Tuesday, Thursday, or Saturday. Among the given options, Tuesday is not possible.

Explanation:

Compute the number of odd days contributed by complete centuries (100-year blocks).

• 100 years → 5 odd days (so the last day shifts by 5 weekdays).

• 200 years → 10 odd days ≡ 3 odd days (shift of 3 weekdays).

• 300 years → 15 odd days ≡ 1 odd day (shift of 1 weekday).

• 400 years → 20 odd days ≡ 0 odd days (no net shift).

Starting from a reference point, these shifts produce the repeating set of possible last weekdays for centuries: Friday (after 100 years), Wednesday (after 200 years), Monday (after 300 years), and Sunday (after 400 years).

Therefore the only possible last days of a century are Friday, Wednesday, Monday, and Sunday. Tuesday, Thursday, and Saturday never occur as the last day of a century.

Note on the given options: among the choices provided, Tuesday is not possible, while Monday, Wednesday, and Friday are possible last days of a century.