Three friends, Martin, Tyreese, and Braydon, are collecting donations to help in their community's clean-up initiative. Their total contribution goal is represented by the expression 9x2 − 4xy + 6. The friends have already collected the following amounts:

Martin: 2xy + 12

Tyreese: x2

Braydon: 3x2 − 5

Which expression represents the amount of money the friends still need to collect to meet their goal?

4x2 + 2xy + 7
5x2 − 6xy − 1
5x2 − 2xy + 13
13x2 − 2xy + 13