Policy Adviser: Freedom of speech is not only a basic human right, it is also the only rational policy for this government to adopt. When ideas are openly aired good idea flourish, silly proposals are easily recognized as such, and dangerous ideas can be responded to by forcing citizens to disseminate their thoughts in secret.
Which one of the following, if true, world most strengthen the argument?

Conclusion: Government should adopt Freedom of speech (FOS) policy.
Premise:
1. FOS is basic human right as well as only rational policy.

Answer should be something that tells obligation to have FOS policy. i.e. Govt will run effectively only in presence of this policy. Or it will not work in absence of FOS policy.

(A) Most citizens would tolerate some limits on freedom of speech -> It weakens saying, govt can do without FOS policy.
(B) With or without a policy of freedom of speech, governments respond to dangerous ideas irrationally. -> Somewhat towards conclusion, but it neighter strenghtens nor weakens. It only says Govt will act irrationally in absence of the policy.
(C) Freedom of religion and freedom of assembly are also basic human rights than governments must recognize. -> No tie with the conclusion.
(D) Governments are less likely to be overthrown if they openly adopt a policy allowing freedom of speech. -> It says Govt. will not be overthrown if FOS policy adopted. In other words, Govt. will be overthrown if FOS policy is not adopted. So, It is the answer.
(E) Great ideas have flourished in societies that repress free speech as often as in those that permit it. -> It repeats whatever said in argument and No tie with conclusion.

what is the source of this question?

My issue is it is not given in the argument what makes something as the most rational for the government to adopt.
Lets say if it was given that the current government is in a danger to save itself then D would have been correct.

I chose A because that even if FOS is given, some dangerous ideas can be constrained by putting some limits which is lacking a support. This is clearly provided by A and thus makes FOS a rational policy as well since nothing should increase the danger.

I chose D but on retrospect agree with OA that A is correct.

D would be wrong because the question does not mention the motive behind allowing of freedom of speech is to prevent the govt from being overthrown.