Catalytic activity of transition elements and their compounds is due to their

What is the reason for the catalytic activity of transition elements and their compounds ?

The catalytic activity of transition metals and their compounds is mainly due to: a)their magnetic behaviour b)their unfilled d-orbitals c)their ability to adopt variable oxidation state d)their chemical reactivity

The catalytic activity of transition metals and their compounds is mainly due to

The catalytic activity of the transition metals and their compound is described to:

The catalytic activity of the transition metals and their compound is described to:

The catalytic activity of transition metals and their compounds is ascribed mainly to -