You are a helpful assistant. When the user asks a question, your response must include two parts: first, the reasoning process enclosed in <think>...</think> tags, then the final answer enclosed in <answer>...</answer> tags.Please provide a clear, concise response within <answer> </answer> tags that directly addresses the question.
system
<image>In February 2014, the New England Journal of Medicine published in the same issue two epidemiological trials (field trials) of inactivated EV71 vaccine conducted by scholars in China respectively. One of the studies was from Jiangsu Province, China, and the study design was a randomised, double-blind, placebo-controlled, multicentre trial (phase III trial), which included a total of 10,077 healthy children aged 6-35 months. The primary outcome indicator was the incidence of EV71-related hand, foot and mouth disease or herpangina, according to the 0- and 28-day immunisation schedule, using block (one group of 10 persons) randomisation, with a 1:1 allocation of study participants to EV71 vaccine or placebo, and follow-up monitoring for 12 months, and the results were shown in the table below.<image 1> The protective rate against all EV71 related diseases was
A. 100%
B. 94.8%
C. 94.6%
D. 88.1%

Please answer the question with option letter from given choices in the format of Answer: <option letter>. You FIRST think about the reasoning process as an internal monologue and then provide the final answer. The reasoning process MUST BE enclosed within <think> </think> tags. Please answer the final answer within the <answer> </answer> tags.
user
D
In February 2014, the New England Journal of Medicine published in the same issue two epidemiological trials (field trials) of inactivated EV71 vaccine conducted by scholars in China respectively. One of the studies was from Jiangsu Province, China, and the study design was a randomised, double-blind, placebo-controlled, multicentre trial (phase III trial), which included a total of 10,077 healthy children aged 6-35 months. The primary outcome indicator was the incidence of EV71-related hand, foot and mouth disease or herpangina, according to the 0- and 28-day immunisation schedule, using block (one group of 10 persons) randomisation, with a 1:1 allocation of study participants to EV71 vaccine or placebo, and follow-up monitoring for 12 months, and the results were shown in the table below.<image 1> The protective rate against all EV71 related diseases was
A. 100%
B. 94.8%
C. 94.6%
D. 88.1%

Please answer the question with option letter from given choices in the format of Answer: <option letter>. You FIRST think about the reasoning process as an internal monologue and then provide the final answer. The reasoning process MUST BE enclosed within <think> </think> tags. Please answer the final answer within the <answer> </answer> tags.
val