Metals are malleable because Athe cations in the lattice are mobile Bthe lattice contains delocalized electrons which can move Cthe atoms in the lattice can roll over each other when pressure is applied Dthe atoms in the lattice are different sizes so can slide past each other

Metals are malleable because of several factors. Let's break it down step by step:

1. The cations in the lattice are mobile: In a metal lattice, the atoms are arranged in a regular pattern. The lattice structure consists of positively charged metal cations surrounded by a sea of delocalized electrons. These cations are not fixed in their positions and can move within the lattice.

2. The lattice contains delocalized electrons which can move: Unlike in non-metallic materials, metals have a unique property where their outermost electrons are not tightly bound to any specific atom. Instead, these electrons are free to move throughout the lattice. This mobility of electrons allows for the malleability of metals.

3. The atoms in the lattice can roll over each other when pressure is applied: When an external force, such as pressure, is applied to a metal, the atoms in the lattice can easily slide past each other. This ability to roll over one another is due to the metallic bonding and the presence of mobile cations and delocalized electrons.

Therefore, the correct answer to why metals are malleable is B: the lattice contains delocalized electrons which can move.