confused about this indicative- subjunctive structure.

[abcdefg]

Because of differences in the human body's internal pressure and the ocean's, it is essential that a diver returning to the surface ascends slowly or they will suffer a painful condition known as the "bends."

Because of differences in the human body's internal pressure and the ocean's, it is essential that a diver returning to the surface ascends slowly or they

Because of the difference between the human body's internal pressure and the ocean's, it is essential that a diver returning to the surface ascend slowly or they

Because of the difference in the human body's internal pressure and that of the ocean, it is essential that a diver returning to the surface ascends slowly or he

Because of differences in the human body's internal pressure and that of the ocean, it is essential that a diver returning to the surface ascend slowly or they

Because of the difference between the internal pressure of the human body and that of the ocean, it is essential that a diver returning to the surface ascend slowly or he

The OA is [spoiler] E. However I'm confused about C, which uses "ascends" instead of "ascend". I thought this would be the right answer because we're using ascends for the singular person he. However the OA says that this is wrong because it uses the indicative mood "ascends" where the subjunctive mood ("ascend") is required. [/spoiler].

Can someone please help me out and how it works? thanks.

[Naruto]

Because of differences in the human body's internal pressure and the ocean's, it is essential that a diver returning to the surface ascends slowly or they will suffer a painful condition known as the "bends."

Because of differences in the human body's internal pressure and the ocean's, it is essential that a diver returning to the surface ascends slowly or they

Because of the difference between the human body's internal pressure and the ocean's, it is essential that a diver returning to the surface ascend slowly or they

Because of the difference in the human body's internal pressure and that of the ocean, it is essential that a diver returning to the surface ascends slowly or he

Because of differences in the human body's internal pressure and that of the ocean, it is essential that a diver returning to the surface ascend slowly or they

Because of the difference between the internal pressure of the human body and that of the ocean, it is essential that a diver returning to the surface ascend slowly or he

The OA is [spoiler] E. However I'm confused about C, which uses "ascends" instead of "ascend". I thought this would be the right answer because we're using ascends for the singular person he. However the OA says that this is wrong because it uses the indicative mood "ascends" where the subjunctive mood ("ascend") is required. [/spoiler].

Can someone please help me out and how it works? thanks.

Since its an instruction, a subjunctive mood is required i.e (as its always 'to ascend' and not 'to ascends') hence E, i hope its clear.

[aspirant_gmat]

Hi abcdefg!

Sentences with subjunctive mood have the following structure regardless of the subject:

that + the infinitive form of the verb without 'to'.

Subjunctive mood is used to represent somebody's recomondation, hope, desire, order etc. for someone else.

For example: I hope that he WIN the game.

In the same manner in this sentence 'essential that' should be followed by 'ascend'.

it is essential that a diver returning to the surface ascend slowly or he

[apoorva.srivastva]

well as others have rightly pointed out the use of subjunctive ...u can also take C out for the unclear comparison between the pressure of the human body and the ocean

E is gives us a clear comparison and uses the subjunctive efficetively :)

[rah_pandey]

difference between X and Y correct idiom

difference in....is wrong