Which of Following Describes Forward Rates

Which of following describes forward rates?

A) Interest rates implied by current zero rates for future periods of time
B) Interest rate earned on an investment that starts today and last for n-years in the future without coupons
C) The coupon rate that causes a bond price to equal its par (or principal) value
D) A single discount rate that gives the value of a bond equal to its market price when applied to all cash flows