The correct option is C heterodont
'Hetero' means different and 'dont' means teeth. Humans have teeth with different morphology such as incisors, canines, pre-molars and molars and hence, are known as heterodont. Also, humans have two successive sets of teeth in different stages of life- deciduous set and permanent set. That is why, they are called diphyodont.
Thecodont is a morphological arrangement in which the base of the tooth is completely enclosed in a deep socket of bone. Dentine is the bone-like substance beneath the enamel.