A. a covalent bond occurs when two ions share a set of electrons and thereby offset their ionic charge. b. a covalent bond occurs when oppositely charged ions attract each other, and the electrons of the negatively charged ion get transferred to the positively charged ion. c. a covalent bond occurs when similarly charged ions attract each other, and the electrons of the positively charged ion get transferred to the negatively charged ion. d. a covalent bond occurs when free-moving electrons are shared among a variety of atoms within a matrix.