Which of the following letter-clusters will replace the question mark (?) in the given series?IQAF, JRBG, KSCH, ?, MUEJ

Let's break down the series position by position:First letter: $\text{I}\to \text{J}\to \text{K}\to \mathbf{L}\to \text{M}$ ($+1$ increase)Second letter: $\text{Q}\to \text{R}\to \text{S}\to \mathbf{T}\to \text{U}$ ($+1$ increase)Third letter: $\text{A}\to \text{B}\to \text{C}\to \mathbf{D}\to \text{E}$ ($+1$ increase)Fourth letter: $\text{F}\to \text{G}\to \text{H}\to \mathbf{I}\to \text{J}$ ($+1$ increase)Combining these positions gives LTDI.