The four mechanisms are as follows:
1) Orographic lifting: Air is forced to rise over a mountainous barrier
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2) Frontal wedging: Warmer, less dense air is forced over cooler, denser air along a front
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<span>3) Convergence: Pileup of horizontal air flow resulting in an upward flow
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<span>4) Localized convective lifting: Unequal surface heating causes localized pockets of air to rise because of their buoyancy. </span><span />
I am so positive it’s D because that’s the only one that makes sense. Trust me
