It is water because when the light coming from the bottom of water will move away from the normal and reaches our eyes. Our eyes cannot see the bent light inside and so we will feel water to be more deeper than kerosene
Sumit Kumar answered this
Water because kerosene is optically less denser than water
Gbn answered this
As kerosene molecules have lower density than the water molecules,the bucket with the water has more depth than the kerosene filled bucket.