Sentence Correction

The board of directors of Aqua Pharmaceuticals has requested the representatives of the new ecological brand to elaborate and further discuss the proposal to add the brand to the company's products so the members of the board have all the necessary information.

The board of directors of Aqua Pharmaceuticals has requested the representatives of the new ecological brand to elaborate and further discuss the proposal to
The board of directors of Aqua Pharmaceuticals has requested the representatives of the new ecological brand to elaborate and further discuss the proposal
Aqua Pharmaceuticals' board of directors have requested the representatives of the new ecological brand to elaborate and further discuss the proposal to
Aqua Pharmaceuticals' board of directors has requested the representatives of the new ecological brand to elaborate on and further discuss the proposal to
The board of directors of Aqua Pharmaceuticals has requested the representatives of the new ecological brand to elaborate and briefly discuss the proposal to

[spoiler]OA: D but what is the object of 'elaborate on'. According to Mitch in the following post, prepositions should be followed by objects
https://www.beatthegmat.com/experts-plea ... 90431.html[/spoiler]

Please help

{A} INCORRECT; if we break the sentence structure "to elaborate the proposal to".. "to further discuss the proposal to" .. we need "elaborate on";
{B} INCORRECT; we need "to" with proposal
{C} INCORRECT; "have" SVA
{D} CORRECT
{E} INCORRECT; if we break the sentence structure "to elaborate the proposal to".. to briefly discuss the proposal to" .. we need "elaborate on"; meaning issue - the sentence say elaborate.. so we need further and not briefly