The correct answer is: b) Roadways.
GSRTC stands for Gujarat State Road Transport Corporation. It is a state-owned transport corporation that operates buses in the Indian state of Gujarat. The corporation was founded in 1960 and has its headquarters in Gandhinagar. GSRTC operates a fleet of over 15,000 buses and serves over 1,000 destinations in Gujarat. The corporation offers a variety of bus services, including inter-city, intra-city, and express services. GSRTC also operates a number of luxury buses, including Volvo buses and Scania buses.
The other options are incorrect because they are not the primary mode of transport offered by GSRTC. Railways, airways, and waterways are all modes of transport that are offered by GSRTC, but they are not the primary mode of transport. The primary mode of transport offered by GSRTC is roadways.