A. *"With India administering 30_40 lakh doses daily, this suggests that existing stocks **are going to be** available for 10_13 days, though there is a considerable variation within the states in the number of doses being made available".*

or

A . *"With India administering 30_40 lakh doses daily, this suggests that existing stocks **could be** available for 10_13 days, though there is a considerable variation within the states in the number of doses being made available" 

I believe both are better answers.


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Ref [Expressing a Future Action: When To Use “Will” And “Going To”.][1]
>Will can be a present tense verb that means to cause something to happen through force of desire. It can also be a modal auxiliary verb in various tenses.
**USE WILL FOR A FAR FURTHER FUTURE ACTION** One important detail about “WILL” is that it is most often used to discuss things or situations that may take a long time to happen.

>WHEN TO USE “**GOING TO**” One huge difference in using GOING TO versus WILL, is that you use GOING TO when the action was already decided on even before speaking of it.

**'will' and 'would'**  [Ref][2]

**would is the past tense form of will** which denotes both ability and certainty. In this scenario we are talking about a future event, we have no need to be polite in this context. It is however "hypothetical" whilst being a possibility as opposed to a certainty therefore I believe **could** would be a more appropriate word.

Because it is a past tense, **would it is used:**

>to talk about the past

>to talk about hypotheses (when we imagine something)

>for politeness.

**Is it could or would?**

>Both could and would are verbs that have many senses.
**Could** is a conditional verb that expresses possibility.
**Would** is a conditional verb that expresses certainty, intent, or both.
Ref [writing explained][3]


  [1]: https://www.gonaturalenglish.com/expressing-a-future-action-will-and-going-to/
  [2]: https://learnenglish.britishcouncil.org/english-grammar-reference/will-and-would
  [3]: https://writingexplained.org/could-vs-would-difference