Calendar arithmetic — If 6 March 2005 was a Sunday, what day of the week was 6 March 2002?

Introduction / Context:
We need to move backward three years from the same calendar date, taking leap years into account, to determine the weekday in 2002.

Given Data / Assumptions:

• 6 Mar 2005 = Sunday.
• Years spanned backward: 2004 (leap), 2003 (non-leap), 2002 (non-leap).
• Going backward across a non-leap year shifts the weekday by −1; across a leap year by −2.

Concept / Approach:
Sum backward shifts.

Step-by-Step Solution:
Back over 2004 (leap): −2 → Sunday → Friday.Back over 2003 (non-leap): −1 → Friday → Thursday.Back over 2002 (non-leap to reach 2002-03-06): −1 more → Thursday → Wednesday.Hence 6 Mar 2002 was Wednesday.

Verification / Alternative check:
Total days difference = 1096; 1096 mod 7 = 4; Sunday − 4 = Wednesday.

Why Other Options Are Wrong:
Tuesday/Saturday/Thursday do not match the computed weekday. The correct day (Wednesday) is not listed, so “None of these.”

Common Pitfalls:
Forgetting the double shift across a leap year or mixing up forward vs backward direction.

Final Answer:
Wednesday, therefore “None of these.”