The U.S. Census Bureau tracks sales per month for various products and services through itsMonthly Retail Trade Survey. Suppose the figure below shows the monthly sales of a particular gift, in millions of dollars, over the course of a certain year.A bar graph titled "Estimated Monthly Sales" has a horizontal axis labeled "Month" with the months of the year from January to December and a vertical axis labeled "Sales($ millions)" with values from 0 to 7,000.

• The bar chart titled "Estimated Monthly Sales" has 12 bars.
• Each bar is associated with a label and an approximate value as listed below.
  • Jan: 1,650
  • Feb: 2,560
  • Mar: 2,040
  • Apr: 2,200
  • May: 2,720
  • Jun: 2,120
  • Jul: 2,020
  • Aug: 2,130
  • Sep: 1,990
  • Oct: 2,080
  • Nov: 2,710
  • Dec: 6,300

(a)Are the data quantitative or categorical?quantitativecategorical (b)Are the data cross-sectional or time series?cross-sectionaltime series (c)Which four months have the highest sales? (Select all that apply.)JanuaryFebruaryMarchAprilMayJuneJulyAugustSeptemberOctoberNovemberDecember (d)What is the most likely cause for the answers to part (c) being the highest four months?Retailers had an insufficient stock of these types of gifts during these months.These months correspond to times of the year when individual incomes increase. These months correspond to various gift giving holidays.These months correspond to the four seasons of the year.Retailers had an excess stock of these types of gifts during these months.