A: The other related equations would be:
K = °C + 273.15
K = °F + 457.87
Note: There are other equations that can be related, these are just ones that I find to be related. This is open to interpretation.
B:
23° C + 273.15 = 269.15 K
C:
300 K - 273.15 = 26.85 °C
300 Kelvins is greater than 25 degrees Celsius.