This question checks whether we test every possible month length before picking a fixed number, instead of assuming just one length.
Since both 4 and 5 show up depending on whether the month has 28, 30 or 31 days, no single fixed count works for every case.
Let's summarize:
So the answer is option D, cannot be specified.
What was the day of the week on \(15^{\text{th}}\) August 2006?