Summing to 1

Which of the following quantities must always sum to 1, no matter what the distribution is? (Assume A and B are binary variables).

-- $P(A=0)~\text{and}~P(A=1)$ $P(A=0~|~B=0)~\text{and}~P(A=1~|~B=0)$ $P(A=0~|~B=0)~\text{and}~P(A=0~|~B=1)$ $P(A=0,~B=0)~\text{and}~P(A=0,~B=1)~\text{and}~P(A=1,~B=0)~\text{and}~P(A=1,~B=1)$ $P(A=0)~\text{and}~P(B=0)$