(a) Rust is hydrated iron oxide and it is not the same as iron.
(b) Rusting of iron leads to the transformation of iron into a new substance rust. It cannot be reversed by any simple method.
(c) Yes, rusting of iron is a chemical change. During the rusting of iron, it combines with oxygen in the presence of water (moisture) to form a new substance called rust. So, rusting of iron is a chemical change.
(d) Burning of paper and cooking of vegetables are two other examples of chemical change.