[B]What to recite during the Best 10 Days:[/B]
"There are no days in which righteous deeds are more beloved to Allaah than these 10 days." [Bukhaari]
"So say tahlil takbir& tahmid a lot [on those days]."
[Reported by Ahmad, 7/224; Ahmad Shakir stated it is saheeh]
a) Say tahlil
La ilaha illah Allah
(note this is one of them)
Laa ilaaha ill-Allaah Walahu Akbar
Wa Lillaahil hamd
(Allaah is Most Great, Allaah is Most Great, there is no god except Allaah, Allaah is Most Great, Allaah is Most Great, and all praise be to Allaah).