It's B.
If 
, then it's also the case that 
, because multiplying any number 
by a number (in this case, also ) between 0 and 1 scales that number down.
It's not C, because 
.
It's not D, because 
.
Answer:
Q ' (3,4)
Step-by-step explanation:
When we reflect across the x axis, the y coordinate becomes -y
Q (3,-4) becomes Q' (3,- -4)
Q ' (3,4)
