(B) drew back
(A) culture .. manners
(B) experiments .. science
(C) experience .. scholarship
(D) learning .. knowing
Since Joshua was undaunted (not discouraged) by his failures, a positive word is necessary. PERSEVERED is the only positive word.
The sentence mentions "Knowledge gained without experience" and then asks for the opposite condition, which must be EXPERIENCE without SCHOLARSHIP.
The opposite of forcing students to take courses is ENTICING them to do so.