New SSD + HDD; master boot record or GPT?

[MillsyOC]

Just entered Disk Management for the first time after My Computer only displayed my OS drive (SSD).

My 2nd SSD and my 2TB HDD are both recognised, but it's asking for me to set them as MBR or GPT.

I'd assume MBR but I want to double check.

Cheers.