2019AMC12A, 23  Define binary operations $$\diamondsuit $$ and $$\heartsuit$$ by $$a\diamondsuit b=a^{\log _7(b)}$$ and $$a\heartsuit b=a^{\frac{1}{\log _7(b)}}$$ for all real numbers $$a$$ and $$b$$ for which these expressions are defined. The sequence $$(a_n)$$ is defined recursively by $$a_3=3\heartsuit 2$$ and $$a_n=(n\heartsuit (n-1))\diamondsuit a_{n-1}$$ for all integers $$n\geqslant 4$$. To the nearest integer, what is $$\log _7(a_{2019})$$?   对所有实数$$a$$, $$b$$, 定义二元运算$$\diamondsuit $$ 和 $$\heartsuit$$如下: $$a\diamondsuit b=a^{\log _7(b)}$$ , $$a\heartsuit b=a^{\frac{1}{\log _7(b)}}$$. 数列 $$(a_n)$$ 满足 $$a_3=3\heartsuit 2$$以及$$a_n=(n\heartsuit (n-1))\diamondsuit a_{n-1}$$ ($$n\geq 4$$). 距离 $$\log _7(a_{2019})$$ 最近的整数是多少? ．
选项为:A:$$8$$  B:$$9$$  C:$$10$$  D:$$11$$  E:$$12$$  请回答其中一个选项.