Let $f ( x , y , z ) = 48.4 - 3.1 x + 7.7 y + 8.5 z$

Multiple Choice

Let $f ( x , y , z ) = 48.4 - 3.1 x + 7.7 y + 8.5 z$ .
By what value is $f$ increased if $y$ is increased by 1

A) 48.4
B) 8.7
C) 56.1
D) $1$
E) 7.7