To model the relationship between the number of months (x) and the total amount of money (y) in Oliwia's account, we start with her initial deposit and the monthly interest.
- Initial deposit: $3,000
- Interest earned per month: $3
After \( x \) months, the total amount of money in her account can be expressed as:
\[ y = \text{initial deposit} + \text{interest per month} \cdot \text{number of months} \]
Plugging in the numbers, we get:
\[ y = 3000 + 3x \]
Therefore, the equation that models the relationship is:
\[ y = 3x + 3000 \]
This matches the last option provided:
y = 3x + 3,000, where x is the number of months and y is the total amount of money Oliwia will have in her account.