To find out which day 1st March was given that 18th March was a Wednesday, we can use the concept of days of the week alongside the calendar structure for March.

1. We know that March has a fixed number of 31 days. Starting from 18th March, we need to count backwards to reach 1st March.
2. Let's calculate the number of days from 1st March to 18th March: 18 - 1 = 17 days.
3. Now, starting from 18th March, which is a Wednesday, count backwards 17 days to find the day of the week on 1st March.
4. Counting 17 days back from Wednesday (18th March):
   • 17 - 7 = 10 (one week back covers 7 days, the remainder is 10 days)
5. Rerun these 10 days:
   • 10 days back from Wednesday: Tuesday (1), Monday (2), Sunday (3), Saturday (4), Friday (5), Thursday (6), Wednesday (7), Tuesday (8), Monday (9), Sunday (10).

Therefore, 1st March was a Sunday.

This verifies that the given correct answer is indeed रविवार (Sunday).