(C): Weight of 2 cylinders and 1 cone = 500g

Weight of 4 cylinders and 3 cones = 1300g

⇒ Weight of ( 2 cylinders and 1 cone + 2 cylinders and 1 cone + 1 cone ) = 1300g

⇒ 500g + 500g + Weight of 1 cone = 1300g

⇒ Weight of 1 cone = 1300 g - 1000 g = 300 g

Also,

Weight of 2 cylinders and 1 cone = 500g

⇒ 300 g + Weight of 2 cylinders = 500 g

⇒ Weight of 2 cylinders = 500g - 300 g = 200 g

⇒ Weight of 1 cylinder = 200 / 2 = 100 g