Astock’s price is determined by the market forces of a. supply and demand b. cost and efficiency c. production and price d. technology and productivity

The correct answer is A.

Prices in the stock market, like in the markets of products and services, are determined by the free interactions of supply and demand. Equilibrum prices  represent how the desires and preferences of consumers and producers meet and once interests are equaled how the resulting prices are the base of the economic transactions undertaken in the market (in the case purchase of a company's stock).

this null effect is caused by a weak manipulation and ineffective internal validity. in a scientific study, as the one dr. morimoto is trying to perfom, internal validity refers to the confidence placed in the cause-effect relationship and to how well an experiment is done and able to eliminate confounding variables.