You are constructing a school building and due to some unforeseen incidents, your project is delayed. To bring the project on schedule, you are thinking about running several activities in parallel which were earlier planned to run sequentially. So, you started reviewing activities such as excavation of foundation, building walls, carpentry work, electrical work, and plumbing work, etc. After the review, you decide to run the carpentry, electrical, and plumbing works together. Excavating the foundation for the construction of a wall is an example of which of the following?

(a) Mandatory dependency

(b) Discretionary dependency

(c) External dependency

(d) Internal dependency