For M 150 grade concrete (1:2:4) the moment of resistance factor is

ANS:B - 8.50

I believe there might be a misunderstanding or a misinterpretation in the provided options. The moment of resistance factor for concrete is typically expressed as a decimal value between 0 and 1. The option "8.50" seems unusually high for a moment of resistance factor, as it exceeds the typical range. Moment of resistance factors are typically less than 1, with values ranging from around 0.8 to 0.9 for normal-strength concrete grades. It's possible that there may have been a typographical error or confusion with the provided options. Without further context or clarification, it's challenging to explain the reasoning behind the value "8.50" in the context of moment of resistance factor for concrete. If you have any additional information or if there's a specific context you're referring to, please provide it, and I'd be happy to assist you further.