Make switch B the root

CORRECT TEXT

Each of these vlans has one host each on its ports
SVI on vlan 1 – ip 192.168.1.11
Switch B Ports 3, 4 connected to ports 3 and 4 on Switch A
Port 15 connected to Port on Router.
Tasks to do:
1. Use non proprietary mode of aggregation with Switch B being the initiator
— Use LACP with B being in Active mode
2. Use non proprietary trunking and no negotiation
— Use switchport mode trunk and switchport trunk encapsulation dot1q
3. Restrict only to the VLANs needed
— Use either VTP pruning or allowed VLAN list. The preferred method is using allowed VLAN list
4. SVI on VLAN 1 with some ip and subnet given
5. Configure switch A so that nodes other side of Router C are accessible
— on switch A the default gateway has to be configured.
6. Make switch B the root

Answer: See the explanation.

Explanation:
on Switch A
verify with show run if you need to create vlans 21-23
int range fa0/9 – 10
switchport mode access
switchport access vlan 21
spanning-tree portfast
no shut
int range fa0/13 – 14
switchport mode access
switchport access vlan 22

spanning-tree portfast
no shut
int range fa0/16 – 16
switchport mode access
switchport access vlan 23
spanning-tree portfast
no shut
int range fa0/3 – 4
channel-protocol lacp
channel group 1 mode passive
no shut
int port-channel 1
switchport mode trunk
switchport trunk encapsulation dot1q
spanning-tree allowed vlans 1,21-23
no shut
int vlan 1
ip address 192.168.1.11 255.255.255.0
no shut
SW B
conf t
interface range fastethernet 0/9-10
switchport mode access
switchport accress vlan 21
spanning-tree portfast
no shut
interface rang fastethernet 0/13-14
switchport mode access
switchport accress vlan 22
spanning-tree portfast
no shut
interface rang fastethernet 0/15-16
switchport mode access
switchport accress vlan 23
spanning-tree portfast
no shut
interface range fastethernet 0/3-4
switchport trunk encapsulation dot1q
switchport trunk native vlan 99
switchport trunk allowed vlan 1,21-23,99
switchport mode trunk

channel-protocol lacp
channel-group 1 mode passsive
no shut
// port-channel 1 automatically created and nothing needs to be configured under it
ip default-gateway 10.10.10.1
// VLAN 1 already configured nothing more to be done on it
SWA
vlan 21
vlan 22
vlan 23
interface range fastethernet 0/3-4
switchport trunk native vlan 99
switchport trunk allowed vlan 1,21-23,99
switchport mode trunk
channel-protocol lacp
channel-group 1 mode active
no shut
spanning-tree vlan 1,21-23,99 root primary