Answer : 1. "Wi-Fi"
Explanation :

A Hotspot is required for internet connectivity.

1. Dial-up is generally the slowest Internet connection and is obsolete these days.

2. This high-speed Internet connection is usually provided by telephone companies.

3. Wi-Fi (Wireless Fidelity) is a technology for WLAN (Wireless Local Area Networking) which requires "radio frequency" to transmit to devices.

4. Digital Subscriber Line (DSL-Digital Subscriber Line) service uses a broadband connection, which makes it faster than dial-up.

5. Cable service connects to the Internet through Cable TV.

6. Internet services are provided by mobile operators through mobile phone connections. 3G and 4G services are most commonly used with mobile phones and tablet computers.