Box 4 should be labeled "product market" because goods and services flow into it in exchange for money payments.
Step-by-step explanation:
Product Market in economics refers to the destination where final goods and services are traded to business as well as common public. The important point worth keeping in mind is that the product market does not account for trade in semi-processed or intermediate products.
E.g. Markets for pharmaceutical products, financial services firms offering a multitude of services such as banking, insurance etc.
Thus, Box 4 should be labelled as “product market” since final foods and services flow into it in exchange for revenue generation thus completing the cycle.