Explanation:
To solve \(\sqrt{\sqrt{64}}\):

1. Find the square root of 64:
\[
\sqrt{64} = 8
\]

2. Find the square root of the result (8):
\[
\sqrt{8} = 2\sqrt{2}
\]

So \(\sqrt{\sqrt{64}} = \sqrt{8} = 2\sqrt{2}\), which simplifies to approximately \(2.828\).

However, among the given options, the closest match is:

B. 2.