Complete the following paragraph by filling in the blanks with the help of the given options :
Dr. Diesel was (a) __ gifted engineer. He (b) __ highly practical and persevering in giving shape (c) __ his ideas. He used to work hard (d) __ the clock.
(a) (iii) a
(b) (ii) was
(c) (iv) to
(d) (i) round
