Answer: as per the complete question, theseare the answers.
A. It can be exchanged for a valuable good.
C. It was used in systems involving a "gold standard."
D. It can be traded for a commodity such as silver.
Explanation:
Money is in fact a medium of exchange and it has made trade and exchange of goods and even services more effective, efficient and less time consuming.
Money can be used to purchase valuable goods. This is possible because money can be used to measure the price of a commodity.
Gold standard is a standard way of setting the value of money. You can find more information about this online.
Just as well as exchanging for valuable goods, money can be used to trade commodities such as silver.
In modern times, money are not made of precious metals. Today they are printed by a government which has the authority to issue money and every citizen of that country is obliged to accept such printed notes and coins as valid money.