Without Graphing the Function, Determine Its Amplitude or Period as Requested

Multiple Choice

Without graphing the function, determine its amplitude or period as requested.
- $y = \frac { 3 } { 4 } \sin \left( - \frac { 4 \pi } { 5 } x \right) \quad$ Find the amplitude.

A) $\frac { 3 } { 8 }$
B) $\frac { 8 \pi } { 3 }$
C) $\frac { 4 \pi } { 5 }$
D) $\frac { 5 } { 2 }$