There are many methods to calculate $$x^{2^k}$$ for some positive integer k and given x.
The first DIRECT METHOD, just multiplies $x$ with itself to find $x^2$ and then multiplies $x$ with $x^2$ to find $x^3$ and keeps going like this till $x^{2^k}$ is found.
Thus for example to find $x^4$ it requires 3 multiplications: ( $x$ with itself to find $x^2$, $x$ with $x^2$ to find $x^3$ and finally $x$ with $x^3$ to find $x^4$.)

On the other hand there is also a second method, the SQUARING METHOD, where we at each stage multiply the last number with itself.
For example to find $x^4$, one first multiplies $x$ with itself to get $x^2$, then one multiplies $x^2$ with itself to get $x^4$.
Notice this second method only took 2 multiplications to find $x^4$.
Answer the following questions:
To calculate $x^{16}$ with the first direct method takes multiplications.
To calculate $x^{16}$ with the second, squaring method takes multiplications.

Which method is more efficient for large k?

A. The DIRECT METHOD is more efficient than the SQUARING METHOD.
B. The SQUARING METHOD is more efficient than the DIRECT METHOD.