It seems that Duolingo has since changed the primary translation of this word to now be "control". The translation "to check" is no longer anywhere to be seen. So, I guess they have changed their mind on this one.
Also, I think originally "to check" was more of a "to keep in check" rather than "to check the condition of".
The iTranslate app doesn't offer "check" as a translation for controlar, either, but it does have "monitor" and "keep under control". It also lists a few senses for use with people: "manage, handle, deal with". But I'd wager they aren't accepted here.
Timor mortis conturbat me.
Control and check are not synonyms. To check can mean to put a stop to something or told it back but control is much broader than that. Control translates directly into Spanish as the same word. There are many word in Spanish that mean to check, depending on the context: verificar, cotejar, contener, revisar, etc.
"Check" doesn't work well here. I don't think Mexicans would use it that way. The following is helpful:
check [sth] vtr verificar⇒ vtr chequear⇒ vtr comprobar⇒ vtr
Please check that the balance of my account is at least four hundred dollars. Por favor, verifique que el saldo de mi cuenta sea por lo menos de cuatrocientos dólares.
I agree with Harrison. We would use 'check' here. The English word control just does not have the same range of meanings as the Spanish word controlar. I did not use check in my answer because I knew it would be marked wrong. So I was forced to use bad English in yet another sloppy example...