$4\mathrm{.}10$ How will marketers change their organic $($unpaid$)$ social media postings in the near future? A survey by Social Media Examiner reported that $65\%$ of B$2$B marketers $($marketers who focus primarily on attracting businesses$)$ plan to increase Linkedln organic social media postings, as compared to $43\%$ of B$2$C marketers $($marketers who primarily target consumers$).$ The survey was based on $1,947$ B$2$B marketers and $3,779$ B$2$C marketers. The following table summarizes the results.

$\backslash$table$[[,$BUSINESS FOCUS$],[\backslash$table$[[$INCREASE$],[$LINKEDIN$],[$POSTINGS$?]],$B$2$B$,$B$2$C$,$Total$],[$Yes$,1,266,1,625,2,891],[$No$,681,2,154,2,835],[$Total$,1,947,3,779,5,726]]$

a$.)$ give an example of a simple event.

b$.)$ give an example of a joint event.

c$.)$ why is the complement of a marketer who plans to increase LinkedIn organic social media postings?

d$.)$ why is a marketer who plans to increase LinkedIn organic social media postings and is a B$2$C marketer a joint event?