Which arithmetic operation is valid for quantities of two different dimensions?

If two quantities, A and B, have different dimensions.
Which of the following arithmetic operations could be physically meaningful.
(a) A + B
(b) B - A
(c) A + B
(d) A/B
(e) AB

You can only multiply and divide two quantities of different dimensions, for example; Speed = Distance / Time; Distance is in meters while time is in Seconds, the answers is in meters/sec.