How many basic wave forms are there?

a.) 1
b.) 2
c.) 3
d.) 4

“other instruments such as gravimeters and magnetometers are also used in the search for petroleum. extracting crude oil normally starts with drilling wells into an underground reservoir. when an oil well has been tapped, a geologist (known on the rig as the "mudlogger") will note its presence. “ this is what i found on google i hope it

Is this a question of an answer

Answer (d) the universe had cooled enough for atoms to combine, protons and neutrons were too far apart to form nuclei;