Medium Access Control: Carrier Sense Multiple Access

a$.$ Consider a scenario where two stations, X and Y$,$ are within each

other's transmission range. If station X begins transmitting, station Y will

overhear X$$s transmission and refrain from transmitting. However, even

though station Y may sense the medium immediately after X starts

transmitting, there is still a possibility that Y might start transmitting,

resulting in a collision with X$\text{'}$s transmission. Briefly explain why this could

happen.

b$.$ Now, assume that station Y starts sensing the medium before

station X begins its transmission. Upon detecting that the medium is idle,

station Y starts its transmission. If station X then begins transmitting after

station Y has started, a collision between X$$s and Y$$s transmissions can occur.

Briefly explain why this might happen.

c$.$ Briefly describe how introducing time slots $($slot time$)$ can help

mitigate the issues highlighted in the scenarios above.