If the 1st day of a leap year is Saturday, then what day lies on 4th March in that year?

The 1st day of the leap year (January 1st) is Saturday.

To find the day on March 4th, we need to count the total number of days from January 1st to March 4th.

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Days from January 1st to March 4th:

January: 31 days

February: 29 days (leap year)

First 4 days of March: 4 days

Total days from January 1st to March 4th $= 31 + 29 + 4 = 64$ days

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Since we're counting from January 1st, the number of days that pass until March 4th is $64 - 1 = 63$ days.

To find the day of the week, we divide by 7:

$63 \div 7 = 9$ with remainder $0$

Since the remainder is 0, March 4th falls on the same day as January 1st.

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January 1st is Saturday.

Therefore, March 4th is also Saturday.

The correct answer is Option 1: Saturday.