Step 1: General principles of interpretation in taxation.
- Tax statutes are strictly construed, but principles of fairness and prevention of absurd results still apply.
Step 2: Application to each statement.
- (a) True — the burden of proof lies on the department when changing a settled interpretation.
- (b) True — while equity generally doesn’t override tax law, equitable interpretation may be preferred if literal meaning leads to injustice.
- (c) True — the “absurdity rule” allows departure from literal meaning to reflect legislative intent.
Since all are correct, the answer is (d).
\[
\boxed{(d)}
\]