Which sentence contains a diptote in the genitive marked by fatḥa?

Noun Case Classes: Type 3 — Diptote (Ghayr Munṣarif)

• رَأَيْتُ عُمَرَ
• جَاءَ عُمَرُ
• مَرَرْتُ بِعُمَرَ
• مَرَرْتُ بِزَيْدٍ