The alphabet of which the letter Sad is a part includes how many letters?
Arabic alphabet: The Arabic alphabet (Arabic: الأَبْجَدِيَّة العَرَبِيَّة‎ ‎ "al-abjadīyah al-ʻarabīyah ", or الحُرُوف العَرَبِيَّة "al-ḥurūf al-ʻarabīyah ") or Arabic abjad is the Arabic script as it is codified for writing the Arabic language. Arabic alphabet:  It is written from right to left in a cursive style and includes 28 letters.
i don't know