What would be the effect on the value of the Specific heat Capacity of water if all temperatures were measured in Kelvins (k) rather than degrees celsius (C). Explain

No difference. The size of a Kelvin degree is the same as a Celsius degree. They only vary in an offset.

If it were measured in degrees Fahrenheit or degrees Rankine, the magnitude of the heat capacity number would be smaller.

A Celsius degree is 9/5 of a Fahrenheit degree.