Which of the following sets of the sequential assignment of participants to four conditions represents the use of blocked random assignment to conditions?

A$)4,3,4,3,2,1,2,1$

B$)1,2,1,3,4,4,2,3$

C$)1,3,2,4,4,2,1,3$

D$)1,2,4,4,1,3,3,4$

E$)1,1,2,2,3,3,4,4$