Why would the introduction of credit paper money checks and banking houses increase

The introduction of credit, paper money, checks and banking houses increased trade because these are forms through which to generate value circulation without the need to carry said values physically or in person. That is, they are ways of activating the economy through representative instruments of value, which thus generate greater capacity to create financial and economic values.

your answer would be (a)

new evidence is discovered.

oversights and errors are corrected,

new technology is applied to evidence.