In which type of e$-$commerce do consumers sell products or services to other consumers through online platforms?

a$.$B$2$C $($Business$-$to$-$Consumer$)$

b$.$C$2$C $($Consumer$-$to$-$Consumer$)$

c$.$B$2$B $($Business$-$to$-$Business$)$

d$.$C$2$B $($Consumer$-$to$-$Business$)$