True or false: if the extra output produced from an additional unit of capital falls as the stock of capital rises, the country is possibly overinvesting in capital.

I would say this would be true as if extra capital like an electric shovel in an open pit mine resulted in a fall of output then of course it should be questioned why that occurred since it is a result that is counterintuitive ie does not make sense as one would expect an increase in capital would result in an increase in output.