Renin release is governed by the juxtaglomerular apparatus, which integrates three inputs. Work through what raises versus lowers renin.
The afferent arteriolar baroreceptor releases more renin when wall stretch falls, i.e., when renal perfusion pressure drops (hypovolemia, hypotension, renal artery stenosis). The macula densa releases more renin when it senses low $NaCl$ delivery, and less when $Na^{+}$ delivery is high. Sympathetic $\beta_1$ activation also augments renin.
Testing the choices: high macula densa sodium $\Rightarrow$ inhibits renin (option 1 wrong); high perfusion pressure $\Rightarrow$ inhibits renin (option 2 wrong); expanded ECF volume $\Rightarrow$ inhibits renin (option 4 wrong). Only reduced renal perfusion pressure increases renin.
\[\boxed{\text{Reduced renal perfusion pressure stimulates renin}}\]