Which of the Following Is the Best Description of an Inconsistent

Which of the following is the best description of an inconsistent statement in the Logic of Statements? "A grammatically correct expression ___________________.

A) used to assert that if an antecedent statement is true, then a consequent statement is true
B) that turns out to be false under every possible assignment of truth values to its component simple statements
C) that turns out to be true under at least one possible assignment of truth values to its component simple statements and false under another possible assignment of truth values to its component simple statements
D) that turns out to be true under every possible assignment of truth values to its component simple statements