storage class for block scope variable

How can I make block scope variable with static specifier?

I would like to make variable 'result' with static specifier. But I couldn't it.

For example,

int8_t sumInt8(int8_T intput1, int8_T intput2)

{

static int8_T result;

result = intput1 + input2;

return result;

}

Which storage class can declare it with static specifier?