In 2G the Network function which has the similar functionalities as HSS is …a.HLRb.VLRc.MSCd.SAE GW

The network function in 2G that has similar functionalities as HSS (Home Subscriber Server) in later generations (3G, 4G) is HLR (Home Location Register).

Here's why:

1. The HLR in 2G networks is a database used for storage and management of subscriptions. It is responsible for holding important information about subscribers, including the services they have access to and their location.

2. The HSS in 3G and 4G networks performs a similar role. It is a central database that contains user-related and subscription-related information. The functionalities of the HSS include functionalities of the HLR.

3. Therefore, the answer is a. HLR.

The other options (VLR, MSC, SAE GW) perform different functions in the network.