If \( 2 \) and \( 6 \) are the roots of the equation \( ax^2+bx+1=0 \), then the quadratic equation, whose roots are \( \dfrac{1}{2a+b} \) and \( \dfrac{1}{6a+b} \), is:
\( 2x^2+11x+12=0 \)
\( x^2+8x+12=0 \)
\( 4x^2+14x+12=0 \)
\( x^2+10x+16=0 \)