Enrolled Actuary Exam Prep

Data for a plan in 2012: Location A B C D Number of employees 41 19 15 XThe plan covers all employees of locations B and D only. Location C is collectively bargained.No employees terminated during 2012 and none are statutorily excludable from the plan. The plan covers at least one HCE. What is the minimum number of employees that must be in Location D so that the plan will pass the participation requirement of IRC section 401(a)(26)?