A) The network layout has much influence over the security of the network. The placement of servers with respect to the firewall and various other computers can affect both network performance and security. There may even be areas of the network that are more secure than others. Some of these areas may be further protected with an additional firewall.
But we know, VLAN is not about only security of network. Moreover it is breaking a network in multiple LAN and also give secure connection to each and every LANs.
B) network simulation is a technique whereby a software program models the behavior of a network by calculating the interaction between the different network entities (routers, switches, nodes, access points, links etc.). Most simulators use discrete event simulation - the modeling of systems in which state variables change at discrete points in time.
That is also not the major objective of VLAN
C) Yes creating virtual private network is work of VLAN but with security. Otherwise intruder, hacker take major advantage of this multiple access of LAN. Suppose the bank transaction, Cradit card, Debit card number must ensure secure connection. Otherwise it cannot be used.
D)Segmenting a network has primary goal as security with division of a network. So, this is the correct choice here