What Concept, Institution or Instrument Is Described by Each of the Phrases

Short Answer

What concept, institution or instrument is described by each of the phrases or sentences listed below?
a. Trading of loans and securities in which any individual or institution can participate.
b. Mechanisms set up by society to trade newly issued loans and securities.
c. Set up to channel temporary cash surpluses into temporary loans.
d. Immediately spendable cash.
e. Assets minus liabilities held by an economic unit.