In Dante's depiction of Hell, which sin is considered the gravest?

Explanation

The sins listed are: A. Excessive indulgence in food and drink (Gluttony), B. Extreme greed for wealth (Avarice), C. Denial of religious truths (Heresy), and D. Betrayal of trust or loyalty (Treachery). According to Dante, treachery is the most severe sin in Hell.