Probability that a non-leap year selected at random contains 53 Sundays is?

The year MUST start on a Sunday. For a leap year, it can start on Saturday or Sunday.

In any period of 400 years there are 303 non-leap years, of which 43 begins and ends with a Sunday, and there are 97 leap years, of which 28 begins with a Saturday or a Sunday.

So the probability in a non-leap year is 43/303, or 14.2%.

And the probability in a leap year is 28/97, or 28.9%