Final answer:
The medical assistant's positive communication is demonstrated in option D, where they reassure the patient that the paperwork won't take long, which is encouraging and shows consideration for the patient's time.
Step-by-step explanation:
In the given examples, the medical assistant demonstrates positive communication in option D: "This paperwork won't take long at all." This statement is positive because it helps to alleviate any concerns the patient may have about the length of time required to complete necessary forms. It's an encouraging statement that implies efficiency and consideration for the patient's time.
Other options, such as telling a patient that they will have to wait (option A), that an injection will hurt (option B), or indicating a lack of time to answer questions (option C), do not demonstrate positive communication. They could potentially increase patient anxiety or give the impression of impatience or lack of empathy.