For calculation of interest compounded half yearly, keeping the principal same, which of the following is the method to calculate final amount.

• A.  double the given annual rate and half the given no. of years in the formula.
• B.  double the given annual rate as well as the given number of years in the formula.
• C.  half the given annual rate as well as the given number of years in the formula.
• D.  half the given annual rate and double the given number of years in the formula.