Select the combination of letters that when sequentially placed in the blanks will create a repetitive pattern.
a_bc_a_bcda_ccd_bcd_
1
a, a, b, c, c, d
2
a, c, b, d, b, d
3
a, d, b, b, a, d
4
a, d, b, b, d, d
Select the combination of letters that when sequentially placed in the blanks will create a repetitive pattern.
a_bc_a_bcda_ccd_bcd_