Use a Graphing Utility to Graph the Function and Then $I ( t ) = - 0.1 t ^ { 2 } + 1.3 t$

Multiple Choice

Use a graphing utility to graph the function and then answer the question.
-The polynomial function $I ( t ) = - 0.1 t ^ { 2 } + 1.3 t$ represents the yearly income (or loss) from a real estate investment, where t is time in years. After what year does income begin to decline?

A) 13
B) 5.5
C) 8.67
D) 6.5