The researcher's conclusion is that the scholars' belief is wrong. This means the researcher's trying to prove that the first government (other than China) to issue a form of paper currency was not the Massachusetts colony in 1690. Why should we believe the Mass. colony in 1690 wasn't the first to issue paper currency (other than China)? Because in 1685, the New France government issued playing cards that had an official value, were used as pay to its soldiers, and could be used to buy goods or converted to coins.

Because this is a Sufficient Assumption question, we know that the premises do not prove the conclusion. There's a gap between the facts we're told about the New France government in 1685 and the claim that the Massachusetts colony in 1690 wasn't the first (besides China) to issue paper currency.

Unlike most Sufficient Assumption questions, it may be difficult to articulate up front the missing piece of the argument. In other questions, we can often pinpoint a new concept in the conclusion that the premises must be connected to. This argument seems less susceptible to that technique, however. It's clear that the author thinks the situation described in New France in 1685 is an example of a government issuing paper currency earlier than 1690. What's not clear is exactly why the author's premises don't yet prove that the New France example involves an issuance of paper currency. After all, we know the government issued playing cards and those playing cards were used in ways that seem to meet the definition of currency (they had a value, they were used to purchase goods, they could be exchanged for coins).

Still, even if we have trouble articulating something specific, we can still go into the answers knowing that we want to pick the answer that, if true, proves what happened in New France in 1685 involved government issuance of paper currency.