Answer:
C. A horizontal stretch to produce a period of
and a vertical compression.
Step-by-step explanation:
We are given the parent function as 
It is given that, transformations are applied to the parent function in order to obtain the function
i.e. 
That is, we see that,
The parent function
is stretched horizontally by the factor of
which gives the function
.
Further, the function is compressed vertically by the factor of
which gives the function
.
Now, we know,
If a function f(x) has period P, then the function cf(bx) will have period
.
Since, the period of
is
, so the period of
is
= 
Hence, we get option C is correct.