Diferent menu in each category

Hi, basically i want this:

1 menu for each category like this:

Menu Home (Dog and Cat are categories):
Home/Dog/Cat

Menu displayed in Dog category:
Dog1/Dog2/Dog3/Dog4

Menu displayed in Cat category:
Cat1/Cat2/Cat3/Cat4/

But the menu displayed in Dog1/Dog2/Dog3/Dog4 and in Cat1/Cat2/Cat3/Cat4/ :
Home/Dog/Cat

I hope u understand me xD

I found this code, but i dont know where i should put it and i dont know how it works:

if( is_category( array( 9, 'food', 'bones' ) ){ // you can use either ID or slug...
        wp_nav_menu( 'a')
    } else if( is_category( array( 99, 'fur', 'flees' ) ) {
        wp_nav_menu('b')
    } else if( is_category( array( 'whatever' ) ) {
        wp_nav_menu('c')
    } else {
        wp_nav_menu('x')
    }