If $$\frac{{4 + 3\sqrt 3 }}{{\sqrt {7 + 4\sqrt 3 } }} = A + \sqrt B {\text{,}}$$then B - A is = ?

If $$\frac{{4 + 3\sqrt 3 }}{{\sqrt {7 + 4\sqrt 3 } }} = A + \sqrt B {\

1.	If $$\frac{{4 + 3\sqrt 3 }}{{\sqrt {7 + 4\sqrt 3 } }} = A + \sqrt B {\text{,}}$$then B - A is = ?
A.	13
B.	${\text{2}}\sqrt {13} $$
C.	3
D.	${\text{3}}\sqrt 3- \sqrt 7 $$
Answer» D. ${\text{3}}\sqrt 3- \sqrt 7 $$