(b)
Alkali metals have only one electron in their ultimate shell, hence they can easily donate electron and act as reductant e.g.,
$\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ Fe_{2}O_{3} + 6Na\ \rightarrow 2Fe + 2Na_{2}O$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.