another hard sentecne correction question

I'll take a stab at this before my lovely day at work begins:

Experts believe that the process of desertification could encompass half the continent should current patterns of land use be allowed that they will continue.

A)should current patterns of land use be allowed that they will continue

This is nonsensical and sort of a run on. I always put the answer into the sentence and read it to see if it is even logical; therefore, it reads: Experts believe that the process of desertification could encompass half the continent should current patterns of land use be allowed that they will continue. Obviously when you read it like this you can see that it is a run on. Should current patterns of land use be allowed. Not sure what the proper error classification is here you should just be able to know this is incorrect if you are a native speaker of English because that they will continue cannot be added onto should current patterns of land use be allowed.

B)should current patterns of land use be allowed to continue

Sensical, concise, no issues, subject verb agreement

C)should there be a continuance of allowed current land use pattern
a continuance of the football game some other day. Coontinuance of allowed land use pattern doesn't make any sense.

d) If there is the allowing of current land use pattern to continue
allowing is in the wrong tense.

e) if there is a continuance of allowed current land use pattern

current land use pattern again is rough B is a better option; although, this was my second choice.

I got B

I do understand that choice B is concise and grammatically right but the use of Could and Sould in a single sentence is giving me an awkward feeling. it seems like the first half of the sentence is a general belive "experts believe that desertification could encompass" and the next half of the sentence is a question "should current patterns of land use be allowed?"
Have a lovely day!

I got it but still feels that sentence is missing something..anyways Thanks

This is an instance of a conditional sentence, a category that contains -if then, should, provided etc.

The sentence under scanner is –

“Experts believe that the process of desertification could encompass half the continent should current patterns of land use be allowed that they will continue”

Whatever follows “Experts believe that” should be a complete sentence. The sentence should also follow the rule of conditional i.e. –
If/should <present tense>, then <future tense/present tense>
If/should <past tense>, then <past tense>
.
.
.

Since THEN part in this example is not underlined and contains “could” i.e. past tense, the IF/SHOULD part must be in past tense.

D and E are out for being in present tense.

C contains continuance of …, making it an awkward syntax.

A is not a complete sentence.

Looking at B, it is in past tense and is a complete sentence. This option seems to be up on brevity as well.
Obviously, B turns out to be a winner.

HTH!!!

Should can serve to imply a condition that is UNLIKELY or UNWELCOME.

Should you arrive first, please don't eat all of the cookies.
The implication here is that I don't EXPECT (or that I don't WANT) you to arrive first.