Paper money
a. has a high intrinsic value.
b. is valuable only because of the legal tender requirement.
c. is the primary medium of exchange in a barter economy.
d. is valuable because it is generally accepted in trade.

D. is valuable because it is generally accepted in trade.

Explanation:

Even if the government tries to imposse a currency the people don't want what ends up happening in the real life is that people save in other currencies or precious metal while use the country's coin and currency for transaction only. In the worst case scanario people will avoid the national currency altogether leading to hiperinflation and destruction of that monetary sign.

For a paper money to exist is important that people recognize it and accepted in trade.