Analyze the relationship between 'Phosagro' and 'MOSCOW' within the context of the input sentence.
Options: director/manager, platform, owned by, headquarters location

MOSCOW Aug 3 Russian fertiliser producer Phosagro said on Monday that its agent Citigroup Global Markets Deutschland had reopened a facility that allows conversions between Phosagro's global depositary receipts (GDRs) and ordinary shares.
headquarters location