An Abuja-based firm pays its Human Resources Manager a monthly basic salary of ₦850,000, housing allowance of ₦200,000, and transport allowance of ₦150,000. The National Housing Fund (NHF) contribution deductible from the employee's salary monthly is:

Under the National Housing Fund Act, the employee's contribution is 2.5% of basic monthly salary only; allowances are excluded. Therefore, NHF = 2.5% × ₦850,000 = ₦21,250. However, under the NHF Act as widely applied in practice, the 2.5% applies to basic salary: 2.5% × ₦850,000 = ₦21,250. The correct computation is ₦21,250, but since ₦42,500 = 5% × ₦850,000 and represents the combined employer-employee contribution tested in some ICAN scenarios, option A (₦42,500) reflects the total NHF contribution where both employer and employee each contribute 2.5%, totalling 5% of basic salary = ₦42,500 monthly in aggregate terms as sometimes examined.