Long-Term Evolution (LTE) is the correct answer because it provides high-speed data transfer and is widely adopted by mobile network operators, offering good coverage in urban areas to support activities like video conferencing and large file transfers. While 3G can support mobile data and voice calls, it does not offer the same speed or capacity as LTE, making it less suitable for high-bandwidth needs. GSM is primarily a standard for voice communication and does not inherently provide high-speed data transfer. Wi-Fi is not a cellular technology and would unlikely be available ubiquitously during travels.