how to use the matrix box to do calculation

https://form.jotform.us/71132686184155

I have created  a  test jotform. I will like to count the choice of A. B , C  applicant,

I don't know how to make it do the calculation

thanks

My colleague is already replying on the duplicate thread you submitted at https://www.jotform.com/answers/1126876

Please follow the same thread for further discussion