A disk page $($B$)$ contains $512$ bytes. The search key $($K$),$ data

record $($R$),$ and page id $($P$)$ use $8$ bytes, $64$ bytes and $4$ bytes, respectively. Data entries use

Alternative $(1),$ i$.$e$.,$ pair $.$ A leaf node has a $$previous$-$leaf pointer$$ and a $$next$-$leaf$-$pointer$$