Final answer:
Using a soft toothbrush is important to prevent complications while taking warfarin.
Step-by-step explanation:
The statement by the client that best indicates an understanding of how to prevent complications while taking warfarin is:
a) 'I should use a soft toothbrush.'
Using a soft toothbrush is important because warfarin can increase the risk of bleeding, so it's important to avoid any activities that may cause bleeding or injury. Using a soft toothbrush helps prevent gum bleeding while brushing.