A continuous frequency distribution of grouped data is represented graphically by a Histogram, where class intervals are taken on the horizontal X-axis and class frequencies on the vertical Y-axis, with adjacent rectangles whose areas are proportional to frequencies.

Why Option 2 is correct: A histogram is specifically designed to graphically depict continuous grouped frequency distributions without gaps between intervals.
Why Option 1 is incorrect: A pie chart is used to show proportions/percentages of categorical or discrete data, not continuous grouped frequency distributions.
Why Option 3 is incorrect: Pictograms use pictures or icons to represent discrete counts or qualitative data.
Why Option 4 is incorrect: Cartograms represent statistical data on geographical maps.

For a binomial distribution $B(n, p)$:
$\text{Mean} = np = 8$
$\text{Variance} = npq = 6$

Dividing variance by mean:

The mode of a binomial distribution is determined by the value of $(n + 1)p$:

Since $(n + 1)p = 8.25$ is not an integer, the distribution is unimodal and the mode is the integral part $[(n + 1)p] = [8.25] = 8$.