Bunuel wrote:

Micah saved $300 of his take-home pay last month. How much was Micah’s takehome pay last month?

(1) From last month’s take-home pay, Micah paid three times as much in rent as he saved.

(2) Micah spent 50% of his take-home pay on living expenses, and saved 25% of the remainder.

We are given that Micah saved an absolute amount equal to $300 last month. And the ask is to find total take home pay.

(1) Does not tell us anything about the total pay as there could be other components & spending/savings to total pay other than rent + savings.

Not suff(2) Tells us Micah saved 25% of the remainder ( which is 50% after he spent 50% on living expenses - could be rent

& other things).

Sufficient as 25% of 50% of take home pay is $300 hence we can find the take home pay.

Hence

Option (B) is correct.