Which of the following represent the addition property of equality?
If a = b and c = d, then a + b = c + d.
If a = b and c = d, then ac = bd.
If a = b and c = d, then a + c = b + d.
If a = b and c = d, then ac + b = bd + a.
If a = b and c = d, then a + b = c + d.
If a = b and c = d, then ac = bd.
If a = b and c = d, then a + c = b + d.
If a = b and c = d, then ac + b = bd + a.