Choose the answer that is the most effective substitute for the underlined part of the sentence. if no substitute is necessary, choose ‘leave as is.’ a. leave as is. b. reading each question carefully, thinking through each answer choice, and carefully mark the correct answer on the answer sheet c. reading each question carefully, think through each answer choice, and carefully marking the correct answer on the answer sheet d. to read each question carefully, thinking through each answer choice, and carefully marking the correct answer on the answer sheet