A nurse in the fertility clinic is educating a client about how to properly measure basal body temperature to assess if ovulation is occurring. The nurse would instruct the client to check their temperature at which time?

Rationale: A. Measuring temperature in the evening is unreliable due to daily activities and fluctuations. B. Basal body temperature should be taken first thing every morning before any physical activity to accurately detect the slight rise associated with ovulation. C. Noon measurements are influenced by daily activity and are not reliable. D. Measuring at midnight is inconvenient and not standard practice.