Select the correct statement(s) regarding Internet Exchange Points (IXPs) and/or Network Access Points (NAPs).

a. IXPs and NAPs are facilities that enable interoperability between autonomous systems at OSI layers 1, 2, and 3b. peering agreements between Internet Service Providers (ISPs) within an IXP or NAP ensures the proper counting of exchanged packets and the application of appropriate surchargesc. IXPs and NAPs are facilities that enable the direct connection of privately owned intranets to the Internetd. all statements are correct