We know that marginal relative frequency is calculated by finding the ratio of joint relative frequency for a particular category (any row total or any column total) by sum of all data values.
Here, it is talking about "travelling out of state" category. So we must divide the total of column "travelling out of state" by the total number of students.
Sum of column "travelling out of state" is 57.
Total number of students are 152.
So marginal relative frequency for "travelling out of state" would be 57 out of 152 or 37.5%.
Hence, option A is correct answer i.e. "she should have divided 57 by 152 : 37.5%"
