What country has the most Abrahamic religions?

It depends entirely on what you consider a distinct Abrahamic religion. Many people simply consider Judaism, Christianity, and Islam as the Abrahamic religions and over half of the world's countries have all three religious groups (although only around 30 countries have more 20,000 Jews).

If you divide out religions by sect and/or include Post-Islamic faiths as Abrahamic, it would narrow the field. Both the United States and Iran have (for different reasons) high levels of religious diversity.