Explanation

Human feces typically contain about 10^11 (hundreds of billions) to 10^12 bacteria per gram, but the question asks for the number of Escherichia cells specifically. E. coli usually makes up a small fraction (less than 1%) of total fecal bacteria. However, in standard medical MCQs for this topic, the accepted answer is often 'Millions' or 'Billions' depending on the specific source and context. Let's re-evaluate. Total bacteria are in the billions/trillions. E. coli count is typically cited as 10^6 to 10^8 per gram of feces. This range falls into 'Millions'. Some sources might say 'Thousands' for low counts, but 'Millions' is the standard textbook answer for E. coli concentration in feces (e.g., 10^6-10^7 CFU/g). Therefore, 'Millions' is the most accurate among the choices.