Answer: Old Testament: Masoretic Text
New Testament: Nestle-Aland Novum Testamentum Graece
Step-by-step explanation:
Old Testament (or Hebrew Bible) text that is closest to the original is the Masoretic Text, which is based on the Hebrew text as preserved by the Masoretes, a group of Jewish scholars who lived between the 6th and 10th centuries CE.
For the New Testament, the most reliable and closest text to the original is the Nestle-Aland Novum Testamentum Graece, which is based on a comprehensive study of the oldest available Greek manuscripts. This Greek text is used as the basis for most modern translations of the New Testament, including the New International Version (NIV) and the New Revised Standard Version (NRSV).
However, this topic is debatable and can vary from person to person and groups to groups and hence the above explanation is purely personal and researched opinion and shouldn't be believed to be final.