According to Jean Piaget, children in formal operational stage

The correct option is are capable of hypothetico-deductive reasoning and propositional thought.

Explanation:

According to Jean Piaget's theory of cognitive development, the formal operational stage is the fourth and final stage, which typically begins around age 11 to 12 and continues into adulthood.

Key characteristics of this stage include:

1. Hypothetico-Deductive Reasoning: Adolescents develop the ability to think abstractly, form hypotheses, and systematically test them to solve problems.

2. Propositional Thought: They can evaluate the logic of verbal statements (propositions) without needing to rely on real-world, concrete objects or scenarios.

Let's look at the other options to understand why they belong to earlier cognitive stages:

- Centration and irreversibility of thought as well as engaging in make-believe and symbolic play are characteristics of the Preoperational Stage (around ages 2 to 7).

- The inability to conserve, classify, and seriate also applies to early stages, whereas mastering conservation, classification, and seriation occurs during the Concrete Operational Stage (around ages 7 to 11).