Option 1 -> Obscure means unclear or hard to understand - this is a synonym of esoteric, not an opposite.
Option 2 -> Cryptic means mysterious or hidden in meaning - this is also a synonym of esoteric, not an opposite.
Option 3 -> Reckless means careless or hasty - this is unrelated to the meaning of esoteric.
Option 4 -> Straightforward means clear, simple, and easy to understand - this is the opposite of esoteric.
Hence, Straightforward -> Esoteric means intended for a small group with specialized knowledge (obscure/complex), while straightforward means clear and easily understood by all -> correct