Which of the following is the formula for Availability? Question 13 options: a) [ (Agreed service time (AST) + downtime) /AST ]* 100 b) [ (Agreed service time (AST) - downtime) /AST ]* 100 c) [ (Agreed service time (AST) * downtime) /AST ]* 100 d) [ (Agreed service time (AST) /downtime) /AST ]* 100