The key to nicotine replacement therapy is the pH-dependent buccal absorption of nicotine. Because the un-ionised form crosses the oral mucosa, the mouth must stay alkaline; acidic drinks such as coffee, cola and citrus juice lower the pH and trap nicotine in its ionised state, so the patient is instructed to avoid them for roughly fifteen minutes before and during chewing the gum or sucking the lozenge $-$ which is exactly why the acidic-food statement is the right answer. Testing the other claims: an equivalent-strength lozenge dissolves fully and actually releases about a quarter more nicotine than gum, so gum being superior is false; varenicline's old boxed warning was for neuropsychiatric effects and was withdrawn after the EAGLES study, not a cardiovascular warning; and orally swallowed nicotine is largely destroyed by first-pass metabolism, so the gastrointestinal route is ineffective. Only the acid-avoidance instruction survives scrutiny.
\[\boxed{\text{Avoid acidic food} \sim 15\ \text{min before oral NRT}}\]