If Ms. Gonzalez borrows $1000 for 4 years from a bank that charges 5% annual simple interest, how much interest will she owe at the end of the four years? How much (in total; interest + principal) will she have to repay?
a) Interest: $200, Total repayment: $1000
b) Interest: $250, Total repayment: $1250
c) Interest: $200, Total repayment: $1200
d) Interest: $250, Total repayment: $1000