Question

where is it expected to find lava solidifying into basalt? at the center of the mid-ocean ridge near the boundary between ocean crust and continental crust in the center of the continents along the continental slope

Explanation:

Basalt is a mafic extrusive igneous rock formed from the cooling of lava at or near the Earth's surface. Mid-ocean ridges are divergent plate boundaries where hot, mafic magma rises from the mantle, erupts as lava, and solidifies to form new oceanic crust, which is primarily basalt. The center of mid-ocean ridges is where this active lava extrusion and solidification occurs. Other locations listed do not produce basalt from lava solidification in the same consistent, primary way: ocean-continental boundaries produce more felsic/intermediate rocks, continental centers have intrusive felsic rocks, and continental slopes are sedimentary environments.

Answer:

at the center of the mid-ocean ridge