Data plotted in the graph appear in the table below.

Demand

$140$

$120$

$100$

$80$

$60$

$40$

$20$

Mon

Tue

wed

Mon

Tue

Wed

Sun

Mon

Tue

Obs #

Day

Demand

Obs #

Day

Demand

Mon

$33$

$12$

Fri

$54$

$2$

Tue

$34$

$13$

Sat

$95$

$3$

Wed

$37$

$14$

Sun

$92$

Thu

$42$

$15$

Mon

$58$

$5$

Fri

$44$

$16$

Tue

$63$

$6$

Sat

$79$

$17$

Wed

$67$

Sun

$86$

$18$

Thu

$70$

$8$

Mon

$51$

$19$

Fri

$74$

Tue

$50$

$20$

Sat

$114$

$10$

Wed

$51$

$21$

Sun

$119$

$11$

Thu

$52$

Refer to Graph $8\mathrm{.}1.$ What is the average demand for the second period?

O $63\mathrm{.}57$

$50\mathrm{.}71$

O $82\mathrm{.}5$

O $93\mathrm{.}5$

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