The correct answer is D) pillar. The structural member indicated by the letter F in illustration D033DG is a pillar, which is a vertical support that transfers the load from the deck above to the structure below. This is in accordance with the typical construction and terminology used in maritime vessels and structures. The other options are incorrect because: A) a girder is a horizontal structural member, B) a deck support is a more general term that could refer to various vertical or horizontal members, and C) "erection" is not a structural member but rather the process of assembling the structure.