在⊙O中，弦AB的长为8cm，圆心O到AB的距离为3cm，则⊙O的面积是（　　）

根据短文，从A、B、C、D四个选项中选择正确答案填空。

    It's December 28th. New Year's Day is 1. Ma Li is in a 2 shop. She wants to buy a blouse 3 her mother. She is happy because she 4 a blue blouse. It looks pretty. She thinks it 5 her mother's trousers well, so she asks the shopkeeper what the 6 is. “198 yuan,” says the shopkeeper. Ma Li is surprised (吃惊的), “Too 7! What's it made of?” The shopkeeper tells her the blouse is made of silk. “Good things always 8 much,” he says.

  “But I have only 190 yuan. Can it be cheaper (更便宜)? I buy it for my mother. ”

  “9. 198 yuan is the last price. But I will lend you 8 yuan.”

  “10? We don’t know each other.”

  “Because I love my mother, too,” says the shopkeeper with a smile (微笑).

已知点A（0，﹣2），椭圆E： $\frac{x^2}{a^2}$ + $\frac{y^2}{b^2}$ =1（a＞b＞0）的离心率为 $\frac{\sqrt{3}}{2}$ ，F是椭圆的焦点，直线AF的斜率为 $\frac{2\sqrt{3}}{3}$ ，O为坐标原点．

（Ⅰ）求E的方程；

（Ⅱ）设过点A的直线l与E相交于P，Q两点，当△OPQ的面积最大时，求l的方程．