If '$$\times$$' means '$$\div$$','$$\div$$ means ' + ', ' + ' means ' – ', ' – ' means '$$\times$$​ ', what will come in place of the question mark (?) in the following equation? 
2 - ( 684 + 228 $$\times$$ 19 ) $$\times$$ 21 $$\div$$ 4 = ?​

Given: ​2 - ( 684 + 228 $$\times$$​ 19 )$$\times$$​ 21$$\div$$​ 4 = ?

​$$\begin{array}{|c|c|} \hline\textbf{Operation preference wise} & \textbf{Symbol} \\\hline\text{Brackets} &[],{}, () \\ \hline \text{Orders, of} & (power), √ (root) , of \\ \hline \text{Division}& ÷ \\ \hline \text{Multiplication} & × \\ \hline \text{Addition} & + \\ \hline \text{Subtraction} & - \\\hline\end{array}$$

New equation is 2 $$\times$$ (684 - 228 $$\div$$ 19 ) $$\div$$ 21 + 4

= 2 $$\times$$ 684 - 12 $$\div$$ 21 + 4

= 2 $$\times$$ 672 $$\div$$ 21 + 4

= 2 $$\times$$ 32 + 4​

= 64 + 4

Thus, correct option is (b).