Which of the following are signs of a fungal nail infection?

Discoloration, thickening, and separation are indeed classic signs of a fungal nail infection. Fungal infections can cause the nail to change color, often becoming yellow, brown, or even white. The thickening of the nail is a result of the infection affecting the nail matrix, which leads to abnormal growth. Additionally, the separation of the nail from the nail bed is a common symptom as the infection can disrupt the normal attachment of the nail. Recognizing these signs is essential for proper diagnosis and treatment of a fungal nail infection, making this the most accurate choice related to the symptoms associated with such an infection.