A student recorded the heights of 50 plants in centimetres, grouped them into class intervals, and then drew vertical bars with small uniform gaps between them. He labelled the graph as a “Histogram of Plant Heights”. What is the error in this representation?
(a) Histogram bars should all have equal widths regardless of the size of the class interval
(b) He should have placed the class intervals on the y-axis and the frequencies on the x-axis
(c) Bars in a histogram must be placed adjacent to each other without gaps
(d) He should have drawn a bar graph because plant height is a categorical variable