Which of the following is true of controlling the schedule during project execution and control?

Which of the following is true of controlling the schedule during project execution and control?

a. small schedule slips are important and require immediate attention

b. schedule creep is acceptable if it results in useful new features at an acceptable cost

c. if work cannot be brought back on schedule, changing the schedule is not an option

d. project managers use variance analysis as the primary guide for deciding whether to recommend actions or changes to the schedule