A system is causal if the output of any time depends only on
(A) Values of input in the past and in the future (B) Values of input at that time and in the past (C) Values of input at that time and in the future (D) none
(A) Values of input in the past and in the future (B) Values of input at that time and in the past (C) Values of input at that time and in the future (D) none