ANS:D - five series.

Rolled steel beam sections mean, I sections.

Five series of rolled steel I section is manufactured in India.

(A) ISJB - INDIAN STANDARD JUNIOR BEAMS.
(B) ISLB - INDIAN STANDARD LIGHT BEAMS.
(C) ISMB - INDIAN STANDARD MEDIUM BEAMS.
(D) ISHB - INDIAN STANDARD HEAVY BEAMS.
(E) ISWB - INDIAN STANDARD WIDE FLANGED BEAMS.