Final answer:
Strategy 3, which involves one-on-one conference sessions to discuss student progress, is the formative strategy that best informs instruction to meet individual needs, as it directly addresses specific learning difficulties.
Step-by-step explanation:
The formative strategy that would inform instruction to help the teacher meet the individual learning needs of each student in the class is C. Strategy 3: Midway through a challenging math unit, the teacher sets up conference sessions with each student to chat with them about their progress and have them explain what they are having difficulty with. This strategy allows the teacher to address individual learning needs by identifying specific areas where a student is struggling and tailoring instruction to meet those needs. This direct interaction provides real-time feedback and the opportunity for the teacher to adjust teaching methods and material accordingly to ensure that each student can achieve their learning goals.