A large atom means that the radius would be large, meaning that the effective nuclear charge is low, therefore a lower electronegativity based on the periodic table. A smaller atom would mean the opposite, therefore a higher electronegativity. This combination would mean that the new molecule is polar.
Also, to answer your question, it would be most likely different from both atoms, as size doesn't really matter in a compound's properties.
The answer is A. Water
Bronsted-Lowry base compounds are those that can accept protons
Bronsted-Lowry Acid Compounds are those that can recieve one
Water / H2O is an Amphoteric compund which mean that its molecul can act as a Base and Acid compound, so the answer is A.
Chlorine. Electronegativity generally increases up and across the periodic table
If there is chloroplasts it’s a plant