The correct option is A True
Let take the case of 2 planes meeting in a line. But we will see it will satisfy for other cases too.
Plane 1 will be ¯r.¯n1=d1
Plane 2 will be ¯r.¯n2=d2
We can write the plane through intersection as (¯r.¯n1−d1)+λ(¯r.¯n2−d2)=0. If we simplify this the form it takes is ¯r.(¯n1+λ¯n2)=d1+λd2. This can be viewed as ¯r.¯n3=d3, which represents the equation of a plane and satisfies for the points on the given planes only when they exist on the line of intersection unless λ=0. Therefore given statement is true.