Study.com or Sophia or Straighterline for English Comp I

[VanillaBean]

Have a relative who is an adult learner who does not do well with CLEP test taking.  She is looking to begin a summer term through a university and needs English Comp I quickly.  

Would you suggest Study.com, Straighterline or Sophia?

I've had a high school junior/senior who has done the questions part of sophia but not the written papers so don't have any knowledge of how Sophia papers are for English Comp I vs Straighterline to be able to give any advice.  

I hadn't considered Study.com but with their new pricing tier this is a competitive option pricing wise but again I'm unfamiliar with the workload.

Any opinions, information, comments welcome