Answer: D. If one country creates all the reserves it can prevent other countries from trading.
Step-by-step explanation:
Ditching the Dollar refers to a movement by nations to reduce the dependence on the US. dollar for transactions.
The USD is the major currency for trade around the world with it accounting for the currency of use in more than 50% of the entire World trade. This was due to the Bretton Woods Agreement and System which at the time pegged the USD to gold and other currencies at certain value to the USD.
The influence the USD gained that day continues today. Countries however are increasing becoming fed up by the United States using the Dollar to impose trade restrictions and sanctions on countries and then requiring everyone to fall in line because trades are mostly done in the currency controlled by the US, the USD.
For instance, when sanctions were imposed on Iran, the European Union looked for alternative means of payment for Iranian oil.
Ditching the Dollar therefore argues that having multiple reserve currencies to choose from is healthy because one country will not be able to control world trade as the US has.