For a prokaryotic gene, basal transcription is defined as
a) the level of transcription produced by the rna polymerase holoenzyme on its own.
b) transcription that originates at the core promoter and +1 site.
c) the level of transcription produced by rna polymerase holoenzyme and an activator protein.
d) the absence of transcription resulting from a repressor protein bound to an operator.
e) the absence of transcription resulting from a repressor protein bound to the core promoter.

Option B, Transcription that originates at the core promoter and +1 site

Explanation:

In basal transcription  process a special class of transcription factors which  are nothing but the protein that binds to specific sites  on DNA (which are also known as promoter sites) with an objective of activating transcription of genetic information from DNA to RNA , specifically messenger RNA. The transcription initiation requires association at promoter site(or regions of DNA that are found in the upstream of the coding region of  a gene)  along with a  σ sub unit

Hence, option B is correct

i think that d. wind is the answer.   i missed the question when i answered a. currents.