To answer this question, let's go through each option to understand why it is correct or incorrect:
Option A) Clients may be validation intensive, consequently requiring powerful hardware - This option is not mentioned in the question statement, so we cannot determine whether it is true or not about 2-tier architecture models. Therefore, it is not relevant to determining the correct answer.
Option B) Any change to one tier typically affects both tiers - This option is incorrect because any change to one tier in a 2-tier architecture model does not typically affect both tiers. In a 2-tier architecture, the client tier and the server tier are separate and can be updated or modified independently.
Option C) Represents a single point of failure - This option is incorrect because a 2-tier architecture model does not represent a single point of failure. In a 2-tier architecture, if one tier fails, it does not necessarily mean that the entire system fails. Failures in one tier can often be isolated and do not affect the other tier.
Option D) Each client makes a direct connection with the server - This option is true about 2-tier architecture models. In a 2-tier architecture, each client directly connects to the server tier, without any intermediate layers or components.
Option E) They are not very maintainable - This option is not mentioned in the question statement, so we cannot determine whether it is true or not about 2-tier architecture models. Therefore, it is not relevant to determining the correct answer.
Option F) They are quite manageable - This option is incorrect because 2-tier architecture models are not considered to be quite manageable. In a 2-tier architecture, managing and maintaining the system can be more complex compared to other architecture models that have more layers or components.
The correct answer is B, C, F. These options are not true about 2-tier architecture models because changes to one tier do not typically affect both tiers, 2-tier architecture models do not represent a single point of failure, and they are not considered quite manageable.