The correct answer is option 3: "The rash in German measles appears on the third day." This statement is not correct.

Measles, or rubeola, typically presents with a rash that appears on the third or fourth day after the onset of other symptoms, such as fever, cough, runny nose, and red, watery eyes. So, option 1 is correct.

Chickenpox, or varicella, on the other hand, develops a rash on the first day of illness. The rash starts as small, red bumps that quickly progress into fluid-filled blisters. Therefore, option 2 is incorrect.

German measles, also known as rubella, causes a rash that usually appears on the face and then spreads to the rest of the body. However, the rash generally appears on the first or second day after the onset of symptoms, not the third day. Thus, option 3 is not correct.

Scarlet fever is a bacterial infection that causes a red rash on the body. The rash typically appears on the second day after the onset of symptoms, including sore throat, fever, and strawberry tongue. This means that option 4 is correct.

In conclusion, option 3 is the statement that is not correct as it inaccurately