The right option is; a) fluid basaltic lava flows out of fissures
Lava plateaus form when fluid basaltic lava flows out of fissures.
Lava plateaus is a type of volcanic plateaus that is formed by the wide eruption of highly fluid basaltic lava from fissures or rifts through various vents without violent explosions. The eruptions are often quiet and non-explosive due to low viscosity of lava and usually occur for a long period of time creating lava flow upon lava flow to produce flood basalts. An example of lava plateaus is the Deccan Traps in North West India
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