State the cardinal number of the following set

$A=$set of letters in the word 'LOOK'.

State the cardinal number of the following set: 

$B=\left\{\mathrm{Triangle},\mathrm{quadrilateral},\mathrm{pentagon}\right\}$

State the cardinal number of the following set

$C=\left\{0\right\}$

State the cardinal number of the following set

$H=${Prime numbers less than $6$}

State the cardinal number of the following set

$D=${colours of a rainbow}

State the cardinal number of the following set

$E=${square numbers less than $6$}.

State the cardinal number of the following set

$F=${quadrilateral with five sides}.

State the cardinal number of the following set

$G=\left\{x|x \in \mathrm{N}, \mathrm{x} \mathrm{lies} \mathrm{between} 5 \mathrm{and} 9 \mathrm{i}.\mathrm{e}, 5<\mathrm{x}<9\right\}$.

Which of the following pair is equal sets?

$A=\left\{3,6,9,12\right\}, B=\left\{\mathrm{Multiples} \mathrm{of} 3\right\}$