Answer:
b. stock of tools, including machines, structures, and equipment, used to produce output.
Explanation:
Physical capital -
It is one of the 3 main factors of production , which are tangible , man - made goods , which helps for the production of the goods and services , is referred to as the physical capital .
It consists of the tools , machinery , equipments etc . that are needed to prepare the goods and services .
Hence , from the given information of the question ,
The correct option ia b.