Answer:
D. Covalent
Step-by-step explanation:
When the molecule is sharing electrons within its atoms, the bonding is covalent.
In the case of methane, CH4 the carbon has four covalent bondings.
Ionic bonding occurs when two ionic atoms (not balanced) get bonding.
In the case of the Sodium Chloride NaCl the sodium (Na) is a positive ion, and the chloride (Cl) is a negative ion.
Together, the molecule gets stabilized.