Why can glucose and galactose not act as inducers for the $lac$ operon?

Given below are two statements:
Statement $I$: In lac operon,the repressor protein binds to the promoter region of the operon and prevents $\text{RNA}$ polymerase from transcribing the operon.
Statement $II$: Regulation of lac operon can also be visualized as regulation of enzyme synthesis by its substrate.
In the light of the above statements,choose the correct answer from the options given below:

Which of the following does not act as an inducer in the $lac$ operon?

Which enzyme will be produced in a cell if there is a nonsense mutation in the lac $Y$ gene?

In eukaryotes,the regulation of gene expression could be exerted at $:-$
$(I)$ Transcriptional level (formation of primary transcript)
$(II)$ Processing level (regulation of splicing)
$(III)$ Transport of $\text{mRNA}$ from nucleus to the cytoplasm
$(IV)$ Translational level
Choose the correct order for given statements $:-$

Identify the $INCORRECT$ statement from the following with reference to lac operon.