Which Two of the Following Statements About Value Added Tax

Which two of the following statements about value added tax (VAT) are correct? A.VAT on sales is known as input tax B. If output tax exceeds input tax, money is due to the HMRC C. If input tax exceeds output tax, money is due to the HMRC. D. VAT on purchases is known as input tax
Which pair of statements is correct?

A) A + C
B) A + B
C) C + D
D) B + D