(I)The Average Lifetime of a Debt Security's Stream of Payments

Multiple Choice

(I) The average lifetime of a debt security's stream of payments is called duration.
(II) The duration of a portfolio is the weighted average of the durations of the individual securities,with the weights reflecting the proportion of the portfolio invested in each.

A) (I) is true, (II) false.
B) (I) is false, (II) true.
C) Both are true.
D) Both are false.