Question

a halogens
b transition metals
c metalloids
d actinides

Explanation:

The yellow - shaded area in the periodic table shown corresponds to the transition metals. Transition metals are found in groups 3 - 12 of the periodic table. Halogens are in group 17, metalloids have a specific diagonal - like region, and actinides are the bottom row of the inner transition metals.

Answer:

B. transition metals