Answer:
D. 6\sqrt{5}-4\sqrt{7}
Step-by-step explanation:
[tex]3\sqrt{5}-2\sqrt{7}+\sqrt{45}-\sqrt{28} \\3\sqrt{5}-2\sqrt{7}+\sqrt{9*5}-\sqrt{4*7}\\3\sqrt{5}-2\sqrt{7} +3\sqrt{5}-2\sqrt{7}\\ 6\sqrt{5}-4\sqrt{7}[/tex]