Among Competing Firms,a Firm's Actions Are Considered Strategic Substitutes When

Among competing firms,a firm's actions are considered strategic substitutes when:

A) increasing one firm's action causes the other firm's optimal reaction to decrease.
B) competing goods are very close substitutes for one another.
C) firms compete on multiple dimensions like price,quantity,and product attributes.
D) one firm's actions do not trigger a reaction from the other firms.
E) firms compete on the basis of price.