Given a DataFrame `storesDF` with an integer column `openDate` representing UNIX epoch timestamps, which code snippet correctly converts these timestamps to a string representation using Java's SimpleDateFormat? The DataFrame structure is as follows: ``` storeId openDate 0 1100746394 1 1474410343 2 1116610009 3 1180035265 4 1408024997 ``` Fill in the blanks in the following code block to achieve this conversion: ```python storesDF.__1__("openDateString", __2__(__3__, __4__)) ``` | Databricks Certified Associate Developer for Apache Spark Quiz - LeetQuiz