SAT Question 776cfa7c: Linear Functions answer and explanation with Desmos solution

Choice A is correct. It's given that $t$ represents the number of monthly deposits. In the given function $f\left(t\right)=100+25t$, the coefficient of $t$ is $25$. This means that for every increase in the value of $t$ by $1$, the value of $f\left(t\right)$ increases by $25$. It follows that with each monthly deposit, the amount in Hana's bank account increased by $$25$.