According to the inverted-U theory, R&D expenditures as a percentage of sales tend to be relatively low in

A) low-concentration industries only
B) high-concentration industries only
C) low- and high-concentration industries
D) low- to middle-concentration industries

Inverted-U Theory

A hypothesis suggesting that there is an optimal level of some variable (such as stress or arousal) for performance, with both too little and too much leading to lower performance.

R&D Expenditures

Funds allocated by governments, institutions, or companies towards research and development activities.

Concentration Industries

Industries where a small number of large firms dominate the market, often leading to less competition and higher prices for consumers.