Necesito esta respuesta porfavor

B

Explanation:

angle a = 40.6°

step-by-step explanation:

for any right angle triangle we know the pythagoras theorem reveals

hypotenuse² = height²+base²

by this formula we will calculate the length of hypotenuse

h² = 6²+7²

⇒ h =√36+49 = √85 = 9.22

now from the given triangle sin a = height/ hypotenuse

                                                sin a = 6/9.22 = 0.651

therefore

so angle a = 40.6°

i believe the correct answer is option b. most eastern european nations joined nato.

though i could be wrong, option d. the eastern european nations were granted complete independence, would be another choice.

hope this ! : )