Well, nowadays the production of the 100cc bikes have been not that much. But even people in India have great passion towards the bikes like Yamaha RX100, Yamaha RX135 which are the lower cc range bikes. Though these bikes have less cc, the pickup and speed are best compared to other bikes as these run in two strokes engine. When it comes to pickup, the vehicles like RX 100 may reach the top speed very quickly when compared to the other bikes which are coming with higher CC and fuel efficiency.
Image Source - https://www.cartoq.com/wp-content/uploads/2018/02/RX100.jpg
When it comes to riding in hills and terrains, the 100CC bikes are highly recommended and suitable for such kind of conditions. It depends totally on how you ride the bike in the hilly slopes upwards. But driving the 100CC bikes like Yamaha RX 100 in hills is well and good when compared to the other bikes. Even you can see many youngsters nowdays own the RX100 and RX135 bikes, Though its production has stopped way back, its still remains as the heartbeat for many youngsters. Hence 100CC bikes are suitable to ride in the hills and terrains.