It is energetically favorable for all atoms to have a complete outer
electron shell. Loosely, the atoms on the left hand side of the periodic
table only have a few extra electrons in their outer shell so it is
energetically favorable for them to lose them. The atoms on the right
hand side of the periodic table almost have enough electrons in their
outer shell and so they have a tendency to gain them.
Once electrons have left an electron shell, an atom will have a positive
charge because it has more protons (positive charges) than electrons
(negative charges). Similarly, an electron which has gained electrons to
complete its outer shell will have a negative charge because it now has
more electrons (negative charge) than protons (positive charge).
The correct option is A. Rutherford model of the atom consider an atom to be made up of a central nucleus with electrons orbiting around it. The nucleus is considered to be tiny, heavy and its positively charged while the electrons are negatively charged. The shortcoming of this model is that it was not able to explain how the positive nucleus was not able to attract the negative electrons and pull them inside the nucleus.
Answer:
The decreasing order of bond length in the carbon - carbon bonds will be:

Explanation:
Bond length is defined as average distance between two nuclei of bonded atoms in a molecule.Bond length is inversely proportional to the number of bonds present between two atoms.
...[1]
Bond energy is defied as amount of energy required to break apart the bond of 1 mole of molecule into their individual atom. Bond energy is directly proportional to the number of bonds present between two atoms.
..[2]
From [1] and [2]:

hybridized
hybridized
hybridized
Extent of overlapping of orbitals in these hybridization;

Higher the overlapping of orbital more closer will be both atoms to each other and shorter will be the bond lenght.
So, the decreasing order of bond length in the carbon - carbon bonds will be:

They are hard solid with a crystal lattice structure... with high melting points