To determine the day of the week on February 13, 1750, we need to consider the number of days that have passed between February 1648 and February 1750.

First, let's calculate the number of days between these two dates.

- From February 1648 to February 1649, there are 365 days in a non-leap year.
- From February 1649 to February 1750, there are 101 years.
- Out of these 101 years, 24 are leap years (every 4th year except for century years not divisible by 400). So there are 24 extra days in this period.
- Additionally, we need to account for the leap year day in 1750, which falls on February 29.

Therefore, the total number of days between February 1648 and February 1750 is 365 + 101 + 24 + 1 = 491 days.

Now, let's find out which day of the week February 13, 1750 falls on.

Since there are 7 days in a week, if we divide 491 by 7, we get a quotient of 70 and a remainder of 1.

This means that 491 days is equal to 70 weeks and 1 additional day.

Since February 13, 1750 is 1 day after a multiple of 7, we can conclude that it falls on the same day of the week as February 12, 1750.

Now, let's determine the day of the week for February 12, 1750.

Since February 12, 1750 is 1 day before a multiple of 7, we need to count backward from a known day of the week.

We know that February 12, 1750 is a Wednesday.

Counting backward, we find that February 11, 1750 is a Tuesday, February 10, 1750 is a Monday, and so on.

Therefore, February 13, 1750 falls on a **Saturday**.

Hence, option C is the correct answer.