Answer:
2,43% annual interest rate
Explanation:
The first part of the exercise are complementary information that you don't have to take into account because the in the final statement in the exercise literally says: "if you do not borrow any money on this credit line during the year". It means that you didn't used the line of credit. so, you only have to convert the interest that in monthly to an annual interest rate with the next formula
annual interest rate= ((1+ monthly interest) ^(12)) -1
the 12 is because a year has 12 months
annual interest rate= ((1+ 0,20%) ^ (12)) -1
annual interest rate = 2,43%
