The following table displays a frequency distribution for the number of crew members on each shuttle mission over a $10-$year period. Let $x$ denote the crew size on a randomly selected shuttle from this time period.

$\backslash$table$[[$Crew size,$4,5,6,7,8],[$Frequency$,2,3,31,20,18]]$

a$.$ Obtain the probability distribution of $x.$

$\backslash$table$[[x,4,5,6,7,8],[P(x),,,,,]]$

b$.$ Find $P(x>5).$

$P(x>5)=$

$($Round to three decimal places as needed.$)$

c$.$ Construct a probability histogram for XChoose the correct histogram below.

A$.$

B$.$

B$.$

C$.$

D$.$