$$\frac{1}{7}=0.\overline{142857}$$, it is a decimal which repeats in cycles of $6$. Every $6$\textsuperscript{th}~digit is $7$. The $1986$\textsuperscript{th} digit is $7$. 
The $1986^{}\text{th}$ digit at the right of the decimal point in the decimal expression of $\dfrac{1}{7}$ is~\uline{~~~~~~~~~~}~. 
(1) $$2$$ 
(2) $$4$$ 
(3) $$5$$ 
(4) $$7$$ 