The following statements can be applied to certain types of wave:
1 Their oscillations are longitudinal.
2 They travel at the speed of light in air.
3 They are used in pre-natal scanning.
4 They are used in thermal imaging.
5 They will not travel through a vacuum.
Which of these statements can be applied to microwaves?

Answer:

7) A

Microwaves are transverse waves. So 1 is not correct.
Microwaves travel at the speed of light. So 2 is correct

For pre-natal scanning, ultrasound is used. So 3 is not correct
Infrared is used for thermal imaging. So 4 is not correct.
Microwaves along with other EM waves travel in vacuum.