'Taq' in Taq polymerase stands for:

The correct answer is Option (4) → Thermus aquaticus

The enzyme is named after the bacterium it comes from, Thermus aquaticus, which lives in hot springs.

Option (4) Thermus aquaticus — Correct.

Note: A similar question was also asked in CUET (UG) 2023 on 30-05-2023 (Slot 1).

NCERT Extract:
Amplification of Gene of Interest Using PCR – “… If the process of replication of DNA is repeated many times, the segment of DNA can be amplified to approximately billion times, i.e., 1 billion copies are made. Such repeated amplification is achieved by the use of a thermostable DNA polymerase (isolated from a bacterium, Thermus aquaticus), which remain active during the high temperature induced denaturation of double stranded DNA.”