Understood, but this gets into a slippery slope. "Sola" literally means "only" and so really a literal word for word translation that you are arguing for is "Only one look is enough." They provide the translation as "Just one look is enough." My point is that there isn't really much (if any) loss in meaning between the three so why would two of them be correct, but the 3rd one wouldn't?
Ultimately, my frustration is that I'm trying to test past certain levels that I already "have" in Spanish, but I get dinged for small things like this. I know the sentence and I'm translating it correctly (IMHO)... I just want to not waste more time retaking the tests to get to the level where I want to be.
I used "gaze" which was a definition in an earlier example, but got dinged for using it here.
According to Spanish dict, "una sólo miranda es suficiente"" is the more correct. However, the English translation would be "only" or "just" (at the very beginning of the sentence). In English ""only"" or "just" need to be defined (i.e, una = one) because they both can refer to 1,2,3,4 +++++ looks (not just one look). "Just" or "only" come at the beginning of a sentence in English because they qualify the statement that follows. In English, this is a very common expression: "ONLY (or JUST) one look is suficiente," ONLY (or JUST) three hours of homework is suficient."
Also, in this context, "glance" is not accepted because it implies a casual (not necessarily directed look). Rather in this sentence "look" is being used to accomplish something specific..and has been determined to be "suficiente"by the speaker to do that. In English, "glance" would not be used in this context.