4. Interrupt priority. Suppose that the interrupt sources Timero clear timer on compare match (CTC), external interrupt 1 (INT1), and the transmit complete serial interrupt are enabled. Answer the following questions. a) (6 Points) What are the interrupt flags that are used/monitored for each interrupt source to determine if it (interrupt source) needs to be serviced? For example, the interrupt flag for Timer0 overflow (OVR) is TOVO. b) (3 Points) What is the order that these interrupt sources are serviced if they occur at the same time? c) (6 Points) What are the vector addresses for each of the enabled interrupt sources? (What is the code memory location where the interrupt service routine starts for each interrupt source?)