You are a project manager managing a large software project

You are a project manager managing a large software project. It has a month long design phase in which the team would be preparing the design documents for independent project modules. Review activity for these modules can begin 15 days after starting the design phase. The 15 days difference between the start of the design phase and the start of the review shows _ _ _ _ _between the two activities.

Lead
Lag
External Dependency
Mandatory Dependency

Lead