Consider the following statements about ultrasonic waves: 1- They can destroy insects. 2- They can clean clothes by removing dust. 3- They can be used for the treatment of diseases. 4- They are automatic Can control doors.

• A. 1 और 2 सही हैं।
• B. 3 और 4 सही हैं।
• C. 1, 2 तथा 3 सही हैं।
• D. All are correct.