Answer : The correct option is, U
Explanation :
As we know that there are four states of matter which are solid, liquid, gas and plasma.
Solid state : In this state, the molecules are arranged in regular and repeating pattern. The molecules are closely packed that means they are fixed and vibrate in place but they can not move from one place to another.
For example : Copper
Liquid state : In this state, the molecules are present in random and irregular pattern. The molecules are closely packed but they can move from one place to another.
For example : water
Gaseous state : In this state, the molecules are present in irregular pattern. The molecules are not closely packed and they can move freely from one place to another and spread out.
For example : Helium gas
Plasma state : In this state, the stars, atoms lose their electrons at very high temperature. The mixture of electrons and nuclei that result is the plasma state of matter.
For example : Sun
In the given incomplete table,
T = solid state
W = example : copper
U = gaseous state
X = example : water
V = plasma state
Hence, the gas would be placed in 'U' box.