In a survey, 26 voters were asked their ages. the results are shown below. given a lower class limit of 20 and a class width of 10, which histogram correctly represents the data?

43 66 56 45 28 21 63 35 67 49 66 32 52 53 48 61 37 53 51 69 40 31 60 48 62 59

i already know the answer but i need someone to explain to me how to get to the answer.

(see attachments for answers)