Order of schema is the number of fixed positions in a given template.
in given template $?10?101?$, the symbol $?$ is a wildcard symbol which means these places have a value of either $0,1$
1) Order schema of $?10?101?=5$ as $5$ places have fixed value. (position 2,3,5,6,7)
2) Order schema of $???0??1=2$ as $2$ places have fixed value. (position 4,7)
Option $(B)$ is correct.
Ref: Genetic Algorithms