"Commerce" means
activity.

A. Business

B. Border

C. Regulation

Business

Explanation:

To be more precise, Commerce is the act of buying or selling something. This could include all varieties of physical goods or services.  Which why it's mostly correlated with business.

Commercial activities generally can be conducted within two spaces. The first one is a A physical space where  both consumers and sellers could directly interact with one another. The second one is a virtual space where both consumers and sellers utilize technology to conduct the commercial activities without having to meet one another.

you should try adrenaline. it kicks in in situations like this.

d. i assume the underlined word is "role." reformat if it isn't.

explanation:

role is closest to part because when replacing words, "playing a vital decision," "playing a vital activity," and "playing a vital dollar" don't make logical sense. the only meaningful choice is "playing a vital part."

this fits one of merriam-webster's definitions of role: "a function or part performed especially in a particular operation or process."