Question

It is highly desirable that you furnished evidence of your expenses before you submit your final accounts. 

• A. It is highly desirable that you furnish evidence of your expenses.
• B. It is highly desirable that you should furnish evidence of your expenses.
• C. It is highly to be desired that you furnish evidences of your expenses.
• D. You should have to supply evidence of your expenses.
• E.

Hint:

In sentences with modal verbs like "desirable," use the base form of the verb following that. Do not add modals like "should."

Answer 1

The Correct Option is A

The sentence has a modal structure in the phrase It is highly desirable that, which is followed by a base form of the verb. In English, after that in such constructions, we usually do not use "should" or a modal verb with the base form of the verb. - Option (A) correctly follows this rule, keeping the verb furnish in its base form. - Option (B) is incorrect because adding should here makes the sentence grammatically incorrect. - Option (C) has a strange structure, and the plural form evidences is also incorrect here. - Option (D) does not fit the context as should have to supply is not grammatically sound in this construction. Therefore, Option (A) is the correct answer. 

Answer 2

The phrase "it is highly desirable that" belongs to a class of expressions demanding the mandative subjunctive, where the clause following "that" uses the bare base form of the verb regardless of subject or tense, so each option can be tested against that rule.

1. Option A: "that you furnish evidence" uses the bare base form "furnish" directly after "that," which is exactly the form the mandative subjunctive requires after an expression of desirability.
2. Option B: "that you should furnish evidence" inserts "should" before the base verb; this is redundant alongside a mandative subjunctive expression like "highly desirable that," making the leaner subjunctive form preferable and this option not the best fit here.
3. Option C: "that you furnish evidences" is grammatically closer in verb form but incorrectly pluralises "evidence," an uncountable noun in this sense, so it introduces an error.
4. Option D: "You should have to supply evidence" mixes the modal "should" with "have to," producing a construction that is not standard English and drops the "that"-clause pattern altogether.

Only option A applies the bare subjunctive correctly without introducing redundancy or a countability error.

Hence, the correct answer is Option A.