The correct answer is option 'A' - Cognition.

Explanation:
Cognition refers to the mental processes and activities related to acquiring, processing, storing, and using information. It involves various cognitive functions such as memory, attention, planning, and problem-solving. These cognitive functions are crucial for learning, understanding, and applying knowledge.

Memory:
Memory is the ability to encode, store, and retrieve information. It is essential for remembering facts, concepts, and experiences. Memory allows individuals to recall previously learned information and build upon it, facilitating the learning process.

Attention:
Attention is the ability to focus and concentrate on specific information or stimuli while filtering out distractions. It helps individuals to selectively process and attend to relevant information, enhancing their learning and understanding.

Planning:
Planning involves creating a strategy or a mental roadmap for achieving a specific goal. It requires thinking ahead, setting objectives, and organizing the steps needed to accomplish the goal. Planning helps individuals to prioritize tasks, manage their time effectively, and make informed decisions.

Problem Solving:
Problem-solving is the cognitive process of identifying, analyzing, and resolving a problem or a challenge. It involves using logical reasoning, critical thinking, and creativity to find solutions. Problem-solving skills enable individuals to overcome obstacles, adapt to new situations, and make informed decisions.

In the given scenario, the teacher is referring to memory, attention, planning, and problem-solving. These cognitive functions are an integral part of cognition. By teaching about these cognitive processes, the teacher is helping students develop their cognitive abilities, which are essential for learning, problem-solving, and overall intellectual development.

By understanding and improving their cognition, students can enhance their learning abilities, critical thinking skills, and academic performance. It also prepares them for various challenges they may encounter in their personal and professional lives, where cognitive skills play a crucial role in decision-making and problem-solving.

Therefore, the teacher is teaching about cognition, which encompasses memory, attention, planning, and problem-solving.