Suppose University students who used cafe faced an outbreak immediately following lunch in the case and there was no continued Infection of the disease then after From 1000 students who ate the lunch, 600 of them were infected with "Y" type of bacteria as revealed by laboratory, 400 had acute darhea and abdomina pain, 100 admitted to hospital for better management and 10 students died of the disease. What is the infectivity rate of the bacteria? a. 60% b. 40% c. 25% d. 66.77%

The infectivity rate of a disease is the proportion of individuals who are infected after exposure to the disease. In this case, the infectivity rate of the bacteria can be calculated as follows:<br /><br />Infectivity rate = (Number of infected individuals / Total number of individuals exposed) x 100<br /><br />Given that 600 out of 1000 students were infected with the bacteria, the infectivity rate can be calculated as:<br /><br />Infectivity rate = (600 / 1000) x 100 = 60%<br /><br />Therefore, the correct answer is a. $60\% $.