In an in Vitro Transcription Assay to Detect the Level $\beta$

In an in vitro transcription assay to detect the level of transcription from a lac operon,one of the RNA precursors was tagged with a fluorescent label on the $\beta$ -phosphate.Which of the following is a likely outcome if transcription occurred?

A) The level of fluorescence would increase along the new RNA strand.
B) Each RNA would have a fluorescent tag on every other nucleotide.
C) The level of fluorescence would be very high in the assay buffer.
D) No fluorescence would be detected in the buffer at the end of the assay.
E) All of the choices are possible.