What is causing the rattling noise?

What is your question?

My 2013 Kia Rio has been making this rattling sound every time I push on the gas. When I first purchased my vehicle, it was just a slight rattle whenever i turned. I didn't think it was a big deal until now. A few weeks later, I took my car in for an oil change at Jiffy Lube, they did not mention anything wrong that could make any sounds. Another month went by and the rattling was getting louder and longer, so I took it back to a different auto-shop and they had mentioned my front driver strut mount was losing and could cause noises. Now my car makes a rattling noise when I accelerate, it will rattle for a while and then go away. I was messing with the gas pedal and notice when I take off the noise appears until I release my foot from the gas or it goes away on its own. My boyfriend thinks it's the transmission fluid but we have no idea how or where to check the fluid.

What makes this problem better or worse?

It's worse when accelerating

How long has your 2013 Kia Rio had this problem?

A few months now