Answer
${}^{140}I,\;{}^{235}Mo,\;{}^{235}Nd,\;{}^{128}In,\;{}^{115}Pd$
Work Step by Step
The given e fission reaction is
${}^{235}U+n\rightarrow X+Y+2n$
The Figure 43-1 of he book shows the distribution by mass number of the fragments that are found when many fission events of ${}^{235}U$ are examined.
From the figure, we can rank the given possibilities for $X$ (or $Y$), most likely first.
The rank for $X$ (or $Y$) is: ${}^{140}I,\;{}^{235}Mo,\;{}^{235}Nd,\;{}^{128}In,\;{}^{115}Pd$
