Final answer:
A second-degree burn is the correct answer as it involves a burn injury that extends deep into the dermis, causing swelling and pain.
Step-by-step explanation:
The correct answer to the question “____ = burn injury deep into the dermis” is (b) Second-degree burn. A second-degree burn affects not only the epidermis but also a portion of the dermis layer of the skin, resulting in swelling and painful blistering. In contrast, a third-degree burn involves the full thickness of the skin, destroying both the epidermis and dermis, and affecting nerve endings and sensory function. A fourth-degree burn is the most severe, reaching even deeper to damage underlying muscle and bone, while first-degree burns only affect the epidermis.