Answer: Option D.
Step-by-step explanation:
The translation is defined as
Where, k is stretch factor.
If 0<k<1, then the graph compressed vertically by factor k and if k>1, then the graph stretch vertically by factor k.
It is given that,
After transformation the function becomes
here, k=4>1, so the graph was stretched vertically by a factor of 4.
Therefore, the correct option is D.