Final answer:
The 'No!' from a child signifies the development of autonomy and is the start of recognizing the self as an individual, separate from the mother. This indicates a key developmental milestone showing their emerging self-concept and independent will.
Step-by-step explanation:
The beginning of a child saying 'No!' typically represents the budding sense of autonomy, which is a significant developmental milestone. Among the options provided, the correct answer is that it begins when 'The child can now see himself as an individual separate from his mother.' This reflects the child's cognitive development in recognizing their self as distinct from others, especially primary caregivers like the mother.
Toddlers develop their independent will during this stage, often known as the 'I do it' stage. The choice to assert 'no' can signal a child's understanding of their individuality and power, and it is a natural progression from earlier developmental milestones such as object permanence and self-recognition. This form of negation or refusal, therefore, has broader implications than just the child's language development; it is a manifestation of their emerging self-concept and autonomy.