The sentence that best supports the idea of commitment to liberty and the willingness to confront challenges is:
A. Let every nation know, whether it wishes us well or ill, that we shall pay any price, bear any burden, meet any hardship, support any friend, oppose any foe, in order to assure the survival and the success of liberty.
This sentence emphasizes the determination to ensure liberty's survival, which aligns closely with the themes of commitment and resilience.