<span>Tier 1
Tier 1 providers have the largest and fastest network connections available. A reasonable definition of a tier 1 provider is a network that can reach every other network on the Internet without purchasing IP transit or paying for peering. You might consider a Tier 1 network to be an ISP for other ISPs. Because of their extremely good connectivity, other network providers pay Tier 1 networks to carry their data for them to other locations. As of this time, there are less than 20 Tier 1 network providers worldwide.</span>
I think it’s B if not it’s D both are similar
The cross join is the type of join that is used to create the query.
<h3>What is a join statement?</h3>
This is the term that is used in database programming in order to refer to the select statement that helps in the combination of the records that are contained in two different tables.
The condition that this is used to make happen is what is called the Join statement. There are different types of this type of condition. They are:
A: Explicit inner join
B: Implicit inner join
C: Outer join
D: Cross join
Read more on database here: brainly.com/question/518894
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An optimization model is a term that describes a model that seeks to find the best solution to meet a specific goal.
<u>Explanation:</u>
An optimization model is a sort of numerical model that endeavors to streamline (boost or limit) a target work without abusing asset requirements; otherwise called scientific programming. This dynamic procedure is known as advancement. It helps discover the appropriate response that yields the best ideal allotments of constrained assets required to meet the best solution.
It likewise assists with accomplishing the "best" plan comparative with a lot of organized criteria or limitations. So an optimization model is a term that depicts a model that looks to locate the best answer to meet a particular objective.