During a week in April, the maximum daytime temperatures in Chandigarh were recorded as follows: Monday 28°C, Tuesday 31°C, Wednesday 29°C, Thursday 32°C, Friday 30°C, Saturday 27°C and Sunday 33°C. Find the range of these temperatures.
a) 5∘C
b) 4∘C
c) 6∘C
d) 7∘C