<grammar xmlns=“relaxng.org/ns/structure/1.0”>
<start> <element> <choice> <choice> <name>a</name> <name>b</name> </choice> <name>c</name> </choice> <empty/> </element> </start>
</grammar>
<grammar xmlns=“relaxng.org/ns/structure/1.0”>
<start> <element> <choice> <choice> <name>a</name> <name>b</name> </choice> <name>c</name> </choice> <empty/> </element> </start>
</grammar>