Interview Attire

I am interviewing soon with the DWR for a HEP operator apprenticeship. I had recently done interviews for trade unions, where work clothing (jeans, long sleeve T-shirt, work boots) are appropriate to wear to the interview. Is it same for the DWR, or would it be more appropriate to wear slacks and a button down?

Bonus: any other insight into the interview is much appreciated.

EDIT: there seems to be some people thinking this is a stupid question. Dressing up for some union interviews will actually hurt your chances because it comes off as stuck-up/prissy, or not suited for manual labor. I found out about this apprenticeship through a skilled trades program, hence wondering if they have a similar mindset. As I have never worked for the state, I am unfamiliar with the culture.