Which of the following statements regarding Gantt charts is true?
a) Gantt charts give a timeline and precedence relationships for each activity of a project.
b) Gantt charts use the four standard spines: Methods, Materials, Manpower, and Machinery.
c) Gantt charts are visual devices that show the duration of activities in a project.
d) Gantt charts are expensive.
e) All of the above are true.