Sentence Correction

In an attempt to produce premium oysters, a firm in Scotland has developed a prototype of a submersible oyster farm, sitting below the surface of the ocean, and it provides ideal conditions for the mollusks' growth.
A. farm, sitting below the surface of the ocean, and it provides
B. farm, sitting below the surface of the ocean for providing
C. farm that sits below the surface of the ocean and providing
D. farm that sits below the surface of the ocean and provides
E. farm that is sitting below the surface of the ocean and it provides

This question was discussed earlier but still unclear so posting again.

OA is D, but i have following confusion:

The second part after AND i believe is logically associated with "a prototype of a submersible oyster farm" NOT with the FIRM. In simpler words its the FARM that provides NOT "a firm in Scotland" that provides...now for this to be correct i think after AND the word THAT should be there in op D, to clearly indicate that the following part "provides..." is a part of the relative clause. Because the word that is missing i can elaborate the structure of Op D in this way

a firm in Scotland has developed a prototype of a submersible oyster farm that sits below the surface of the ocean and [a firm in Scotland] provides ideal conditions for the mollusks' growth.

so if u notice my issue is that the part after AND should be a part of relative clause (THAT) and thats why Op D has to be like this:

Modified Op D

a firm in Scotland has developed a prototype of a submersible oyster farm that sits below the surface of the ocean and THAT ideal conditions for the mollusks' growth.

Here THAT will clearly refer to "oyster farm" which is logical i think. Please clear, m i interpreting the wrong logical meaning or there is something wrong with my parallelism concept???