Answer: Deidra is showing formal operational thinking.
Explanation:
The theory of Cognitive Development was developed by Jean Piaget. The theory declares that the human being goes through 4 stages of development progressively throughout life, each distinguished by a characteristic way of thinking.
The stages are:
1. Sensory-motor stage 0 - 24 months.
2. Pre-operational stage 2 - 7 years.
3. Stage of concrete operations 7 - 11 years.
4. Stage of formal operations 11+ years
In this case, Deidra is showing the 4th stage of thinking, characterized by the use of logic, abstract thinking and problem-solving.
I hope this information can help you.