Final answer:
The correct representation of the logical statement 'The whole number has one digit if and only if the whole number is less than 10' is represented by the biconditional operator, which is option D. p ↔ q.
Step-by-step explanation:
The logical statement 'The whole number has one digit if and only if the whole number is less than 10' is an example of a biconditional, which is represented by the logical operator 'if and only if'. The biconditional operator is denoted as 'p ↔ q', where 'p' is the proposition 'The whole number has one digit' and 'q' is the proposition 'The whole number is less than 10'. The correct representation of the statement is D. p ↔ q, which indicates that both propositions must be true or both must be false for the biconditional statement to be true.