According to Standard II (B) - Market Manipulation, transaction-based manipulation occurs when a member or candidate knows or should know that their actions could influence the pricing of a security. This includes securing a dominant position in a financial instrument to exploit and manipulate the price of a related derivative or underlying asset. In this case, the member's actions align with transaction-based manipulation, as they did not involve spreading false rumors or similar activities, which would constitute information-based manipulation. Therefore, options B and C are incorrect.