Weekday shift across a non-leap year boundary: If January 3, 2007 was a Wednesday, what weekday was January 3, 2008?

Introduction / Context:
We are asked to find the weekday on the same calendar date one year later. The key is whether the intervening year is a leap year and whether Feb 29 lies within the interval affecting the shift.

Given Data / Assumptions:

• Start: Jan 3, 2007 (Wednesday).
• End: Jan 3, 2008.
• 2007 is not a leap year (365 days).

Concept / Approach:
From a date D in year Y to the same date D in year Y+1, the weekday shifts by +1 for a normal year (365 ≡ 1 mod 7), and by +2 only when the span includes Feb 29 (i.e., when the starting date is on/after March in a leap-to-next-year span). Here, we traverse one normal year (no Feb 29 inside the span before the endpoint).

Step-by-Step Solution:
1) Days elapsed: 365 (non-leap year 2007).2) 365 mod 7 = 1 ⇒ weekday advances by +1.3) Wednesday + 1 day = Thursday.

Verification / Alternative check:
Since the destination date (Jan 3, 2008) lies before Feb 29, even though 2008 is leap year, the extra day does not affect this span.

Why Other Options Are Wrong:
Tuesday is −1; Friday/Saturday imply +2/+3, which do not apply here.

Common Pitfalls:
Assuming any leap year nearby automatically adds +2 days; forgetting the mod-7 behavior.

Final Answer:
Thursday