The following table represents a plan for a project:

TIMES $($DAYS$)$

JOB NO$.$ PREDECESSOR

JOB$($S$)$ a m b

$1234$

$21123$

$314512$

$413411$

$52135$

$63123$

$74189$

$85,6246$

$982412$

$107345$

$119,10578$

b$.$ Indicate the critical path. multiple choice $1$

$1-3-6-8-9-11$

$1-4-7-10-11$

$1-2-5-8-9-11$

c$.$ What is the expected completion time for the project? $($Do not round intermediate calculations. Round your answer to $2$ decimal places.$)$

d$.$ You can accomplish any one of the following at an additional cost of $$1,500.$ If you will save $$1,000$ for each day that the earliest completion time is reduced, which of the following actions should be taken, if any?