Correct option is D

(b) Aback
(c) Abide
(d) Aboriginal
Aback comes first (starts with "Abac").
Abide comes next (starts with "Abid").
Abode follows (starts with "Abod").
Aboriginal comes last (starts with "Abo", but "Abor" comes after "Abod").
Thus, the correct option is (d) Aboriginal (Comes last in dictionary order).