clearest
adj.adj. the most easy to see, hear, or understand. You use this when comparing three or more things to say which one is the most obvious or simple.
adj. superlative form of 'clear'; most transparent, distinct, or easily understood. Typically used to compare three or more entities in terms of lucidity or visibility.
This is the clearest photo I have of the mountains.
After reviewing all the evidence, the detective found that the clearest explanation was also the simplest one.
The clearest signal of economic recovery appeared in the quarterly reports, which showed a significant and sustained increase in consumer spending across all major sectors.
Superlative adjective — usually preceded by the definite article 'the'.
the most clearestthe clearestDouble superlatives are incorrect; 'clearest' already contains the superlative meaning, so 'most' is redundant.