Barry agrees to teach a course consisting of 10 lectures on Advanced Mathematics at a Polytechnic. His fee is S$10,000. He receives half of it before the course commences, with the other half payable upon completion of the course. What happens if

(a) Polytechnic closes down because of mismanagement after Barry has delivered his eighth lecture?

(b) Barry is fatally injured in a car accident before the commencement of term?

(c) Barry is very irresponsible and fails to turn up to every other lecture?

Restrict your content using entire and divisible contract.