I believe the correct alternative is: A. The ability of one atom to attract the electron of another atom.
Electronegativity is like a magnet's power in atoms, it shows how much an atom attracts electrons from other atoms. If an atom has high electronegativity, it's like a strong magnet, pulling electrons closer. If it has low electronegativity, it's like a weaker magnet, not pulling electrons as strongly. Think of it as a rope!