Representative elements belong to:A. s- and p-blocksB. d-blockC. d- and f- blocksD. f-blocks

The correct answer is: A. s- and p-blocks

Explanation:
The representative elements are those elements found in the s-block and p-block of the periodic table. These elements include groups 1 and 2 (alkali metals and alkaline earth metals) in the s-block and groups 13 to 18 (boron group, carbon group, nitrogen group, oxygen group, halogens, and noble gases) in the p-block.

Breakdown of the blocks:
s-block elements: These are elements where the last electron enters an s-orbital. It includes Group 1 (alkali metals) and Group 2 (alkaline earth metals).
p-block elements: These are elements where the last electron enters a p-orbital. It includes elements from Group 13 to Group 18.
The d-block and f-block elements are transition elements and inner transition elements, respectively, and they are not considered as representative elements.

d-block elements (option B) are transition metals.
f-block elements (option C and D) are lanthanides and actinides, which are inner transition metals.
Hence, the representative elements belong to s- and p-blocks.