The daily output (in thousands of units) of two factories over a fortnight is summarised below:
Factory A
Class (units): 10–1415–1920–24
Frequency: 483
Factory B
Class (units): 10–1415–1920–24
Frequency: 267
Based on standard deviation, which factory has the more consistent daily output?
(a) Factory B
(b) Both factories are equally consistent
(c) Factory A
(d) Consistency cannot be determined from the given grouped data