Step 1: Article 109 framework.
A Money Bill can be introduced only in the Lok Sabha. After passage, it is transmitted to the Rajya Sabha, which may recommend amendments within 14 days.
Step 2: Effect of no action or disagreement.
If the Rajya Sabha does not return the Bill within 14 days, it is deemed passed {in the form passed by the Lok Sabha}. The LS may accept or reject any recommendations.
Step 3: Conclude.
\[
\boxed{\text{Rajya Sabha’s window is 14 days (Option C).}}
\]