If a and b are two physical quantities having different dimensions then which of the following can denote a new physical quantity

If P,Q, R are physical quantities having different dimensions which of the following can never be a meaningful quantity?

If P, Q and R are physical quantities having different dimensions, which of the following combinations can never be a meaningful quantity ?

If P, Q and R are physical quantities, having different dimensions, which of the following combination can never be a meaningful quantity?

The physical quantities not having same dimensions are

The physical quantities not having same dimensions are

The physical quantities not having same dimensions are