Which sentence is written in a formal style and uses an objective tone?

a. i feel that reading an excellent book is a super-efficient use of time.

b. increasing the availability of books to children can improve their reading skills.

c. reading books together is an awesome way for parents to connect with their kids.

d. for me personally, books have always been a great source of comfort.

B. Increasing the availability of books to children can help improve their reading skills.

Explanation:

The adjectives super-efficient (A), awesome (C), great (D) do not belong to a formal style, and they can hardly impart an objective tone to a text.

Only sentence B is written in a formal style and uses an objective tone.

comfortable

explanation:

one type of the adjectives is predicate adjective. a predicate adjective is an adjective which follows a linking verb and modifies or refers back to the main subject of that linking verb.

it usually is used just before the noun it modies.

here in this example:

'penguins seem comfortable in the coolest habitats', comfortable is the predicate adjective which follows the linking verb 'seem' and modifies the noun.