Twin type has less to do with what twins look like and more to do with how they formed.
Identical, or monozygotic, twins form when a single fertilized egg splits and develop as two babies in the uterus. Identical twins originate from the same combination of cells and have the same genetic origin. They are ALWAYS the same sex, two girls/two boys. They may look very similar and it may be difficult to tell them apart.
Fraternal, or dizygotic, twins are two individuals from the same pregnancy who from TWO SEPARATE eggs fertilized by TWO SEPARATE SPERM. The genetic similarity between fraternal twins is the same as any two siblings, about 50 percent. They can be boys, girls, or one of each.
A beam of laser is directed at a reflecting surface put on the moon when the beam of laser is reflected a receiver on the each measure the time since the beam was sent till it was received. Laser is simply light so it has constant velocity in vacuum ~ air (c = 3 x 10^8 m/s)
to find the distance:
t : time measured between launching the beam and receiving it
d : distance
d = ct
I believe your answer should be C. Speed.