What forms when an underwater volcano erupts causing magma to cool quickly?

To be honest I've studied things like this and I feel as if i have a few answers.

#1 basalt- a type of stone that is made when "magma" makes contact with water.

#2 seamounts- these are very similar to island but also very different. Seamounts are basically an underwater mountain that does not pierce the surface of the body do water it is located in.

#3 obsidian- a type of stone or crystal that si made from when magma cools to quickly making a dark on color glossy crystal.

#4 granite- a type of stone that has crystals all in the surface and the body of the rock and granite is formed from magma cooling at a normal speed but with parts that form quicker then others leaving the small crystals .

I hope one of there is the correct answer's and is what your looking for, have a great day. Good luck on your test's

-Harley

(BTW the only reason i put 4 is cause u gave no answer choice)