const int switchPin $=2$; int switchState $=-1$; $//*$ void setup$()\{$ Serial.begin$(115200)$; pinMode$($switchPin$,$ INPUT$)$; digitalWrite$($switchPin$,$ HIGH$)$; $\}$ void loop$()\{$ switchState $=$ digitalRead$($switchPin$)$; Serial.println$($switchState$)$; delay$(10)$; $\}$ Question $3[3$ marks$]$ In the above code for a microswitch, what does the line commented with a $*$ do$?$ A$.$ Decreases the value of switchState from $2$ to $1$ B$.$ Activates a pull$-$up resistor on pin $-1$ C$.$ Initialises switchState to an impossible value before reading D$.$ Converts the value read in on switchPin from analogue to digital