(A) smarter
(B) smarter than
(C) smarter than those
(D) more smarter than

(A) other
(B) the other
(C) another
(D) others

(A) and
(B) or
(C) which
(D) but

butintroduces something in contrast or unexpectedMore (Definitions, Synonyms, Translation)

(A) walked
(B) had walked
(C) has been walking
(D) had been walking

(A) consider
(B) considers
(C) recognize
(D) recognizes

(A) no
(B) nor
(C) or
(D) and

(A) both
(B) until
(C) neither
(D) either

eitherafter a negative statement used as an intensive meaning something like ‘likewise’ or ‘also’More (Definitions, Synonyms, Translation)

(A) who
(B) whose
(C) whom
(D) which

(A) who
(B) whose
(C) whom
(D) which

(A) will purchase
(B) would purchase
(C) would have purchased
(D) have purchased