Step 1: Understand the history of WHO.
The World Health Organization (WHO) was established on 7th April 1948 as the United Nations specialized agency for health, headquartered in Geneva, Switzerland.
Step 2: Analyze the options.
The WHO was established on 7th April, 1948, which corresponds to option (B). The other dates are incorrect.
Step 3: Conclusion.
The WHO was established on 7th April, 1948, making option (B) the correct answer.
Conclusion: The correct answer is (B) 7th April, 1948.
Let the function $ f(x) $ be defined as follows: $$ f(x) = \begin{cases} (1 + | \sin x |)^{\frac{a}{|\sin x|}}, & -\frac{\pi}{6}<x<0 \\b, & x = 0 \\ \frac{\tan 2x}{\tan 3x}, & 0<x<\frac{\pi}{6} \end{cases} $$ Then the values of $ a $ and $ b $ are: