You need to specify the namespaces for the query e.g.

; with xmlnamespaces ('#RowsetSchema' as z)

select

Tbl.Col.value('@ItemCode', 'varchar(8)'),

Tbl.Col.value('@OptionPrice_Code', 'bigint'),

Tbl.Col.value('@OptionName_Code', 'bigint')

from

@x.nodes('//z:row') Tbl(Col)

produces:

0207740011006

0207740051009

0207750011006

0207750051009

02078100549