What command would you use to determine the modem’s IRQ (the modem is on COM1) ?

It’s 4am and you still don’t have your brand new serial modem working. You start suspecting there’s an IRQ conflict somewhere in the system. What command would you use to determine the modem’s IRQ (the modem is on COM1) ?

A.
setserial /dev/ttyS0

B.
cat /proc/interrupts

C.
getserial /dev/ttyS0

D.
cat /proc/irqs

Explanation:
setserial is a program designed to set and/or report the configuration information associated with a serial port. This information includes what I/O port and IRQ a particular serial port is using, and whether or not the break key should be interpreted as the Secure Attention Key, and so on.