; or (ii) the income-based repayment plan under section 493C(f). (B) Selection by the Secretary If a borrower of a loan made under this part on or after July 1, 2018, does not select a repayment plan described in subparagraph (A), the Secretary may provide the borrower with a standard repayment plan under section 455(d)(1)(A) with a repayment period of 10 years. (C) Changes in selections Beginning on July 1, 2018, a borrower of a loan made under this part may change the borrower's selection of a repayment plan in accordance with paragraph (7) and under such terms and conditions as may be established by the Secretary. (D) Borrower in default Beginning on July 1, 2018, the Secretary may require any borrower who has defaulted on a loan made under this part to— (i) pay all reasonable collection costs associated with such loan; and (ii) repay the loan pursuant to an income-based repayment plan under section 493C(f). ; and (3) by adding at the end the following: (7) Borrowers of loans made before July 1, 2018 A borrower who is in repayment on a loan made under part B or part D before July 1, 2018— (A) may choose to retain the repayment plan that the borrower was enrolled in on the day before such date; (B) may elect to— (i) enter the income-based repayment plan under section 493C(f); (ii) enter a standard repayment plan under section 455(d)(1)(A) with a repayment period of 10 years; or (iii) switch between the repayment plans described in clauses (i) and (ii) not more than once during a calendar year; (C) after electing to leave a repayment plan other than an income-based repayment plan described under this subsection or a standard repayment plan under section 455(d)(1)(A), shall not be permitted to re-elect a repayment plan that is not an income-based repayment plan under this subsection or a standard repayment plan under section 455(d)(1)(A)