MAC address consists of $6$ Byte or $48$ bit.To identify MAC address is unicast, multicast, or broadcast we have to check first $8$ bit of the MAC address.
- if the LSB of the first byte is $0$ then it is unicast.
- if the LSB of the first byte is $1$ then it is multi-cast.
- if all the bits are $1$ in MAC address then it is broadcast.
Here given MAC address is $4A:30:10:21:10:1A$. we have to convert the first octet into binary representation and check its LSB bit is $0/1$.
so $4A$ can be written as:$01001010$, its LSB bit is $0$ so it is unicast address.
Option (A) is correct.