$2.$ At the beginning of a project, a software team project manager is given a schedule with everyones vacations on it$.$ She realizes that because the software will be delivered to the quality assurance team exactly when they have overlapping vacations, there is a serious risk of quality problems because there wont be anyone to test the software before it goes into production. What BEST describes the constraint this places on the project?

a$.$ Quality constraint

b$.$ Time constraint

c$.$ Resource constraint

d$.$ Risk constraint