What is the oxidation number of an element? A. The group number for the element
O B. The number of valence electrons an element has
O C. The charge an element would have if it lost or gained electrons
D. The number of atoms of an element in a formula

option C is correct

Explanation:

oxidation number is the apparent charge on an atom which it acquire after lose or gain of electron

the best answer is d because the strong cohesion is caused by the ability of water molecules to undergo hydrogen bonding.

a is incorrect because when water solidifies, it becomes   ice, which expands and occupies a bigger volume for the same mass of water in its liquid state.

b is incorrect because water has high surface tension. besides bonding to itself it hydrogen bonds to other molecules at the top decreasing possibility for breaking of attractive forces.

c is incorrect because the water molecule has oxygen which is highly electronegative and so pulls the electron pair towards itself creating a dipole moment, making the molecule polar.

e is incorrect because water has strong adhesion, ability to stick to other molecules such as glass because of this molecules having stronger hydrogen bonding than water.