Answer:
c. An overflow error
Explanation:
When a variable's value reaches a point that exceeds the maximum capacity of that variable's type (int, float, double, and so on), the system launches an "overflow error", because the value over-flows the maximum capacity of the variable defined type.
Just imagine a glass of water... you keep filling it.. at one point, you'll have too much water to be contained inside the glass and water will overflow... and you will spill it all over. It's basically the same thing with variables and values.
That's why it's important to know the data that will be stored in a variable in order to plan for its full-range and determine which type fits best.