<image>A student, after learning about statistics, conducted a survey on every classmate regarding the 5 types of unhealthy dental habits listed in the table (each respondent must choose and can only choose one from the 5 types of unhealthy dental habits). The survey results are shown in the following statistical chart. Based on the information provided in the chart, answer the following questions:
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(1) How many students are in this class?
(2) How many students in this class have unhealthy dental habits of type C? What percentage of the whole class does this represent?
(3) Please complete the bar chart;
(4) Based on the survey results, estimate the number of students with type B unhealthy dental habits in a grade of 850 students.
