First of all, look for the peak value after which the value again starts to decrease.
Interpolating from the table, as we can see peak values have a 4 day gap.
So the period is 4 days
Here, the peak value = sum of all peak / number of peaks = 129.5
Here the mean values = are sum of all value/ total days =101
Hence, amplitude = 2(peak-mean) = (129.5-101) = 19.5 = 20
Therefore, the correct answer is B) periodic with a period of 4 and amplitude of about 20
