If for \( p\neq q\neq 0 \), the function \( f(x)=\dfrac{\sqrt[7]{\,p(729+x)\,}-3}{\sqrt[3]{\,729+qx\,}-9} \) is continuous at \( x=0 \), then:
\( 7pq\,f(0)-1=0 \)
\( 63q\,f(0)-p^{2}=0 \)
\( 21q\,f(0)-p^{2}=0 \)
\( 7pq\,f(0)-9=0 \)
