<s>[INST] context: Theories and concepts of thumb sucking
Psychosexual/psychoanalytical theory by Sigmund Freud:
According to this, a child goes through various distinct phases of psychological development. In oral phase, it is believed that the mouth is an erogenous zone. During this phase,  the child takes anything and everything to the oral cavity. It is believed that any kind of deprivation of this activity will lead to fixation resulting in oral habits.
Oral drive theory by Sears and Wise (1960):
Strength of oral drive is, in part, a function of how long a child continues to feed by sucking. The oral drive is strengthened by prolongation of nursing; this is the cause and not the frustration of weaning.
Rooting reflex by Benjamin (1962): 
The rooting reflex is movement of the infant’s head and tongue towards an object touching its cheeks. He suggested that, it arises from the rooting and placing reflexes common to all mammalian infants during the first 3 months of life. 
Pediatric Dentistry, Principles and Practice / M.S. Muthu, N. Sivakumar - 2nd Ed  pdf no: 1057 [/INST] question: Who gave the oral drive theory? | options: A: Benjamin B: Sigmund Freud C: Sears & Wise D: Sheldon | answer: C </s>