B because inner core has metal and it’s solid
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Low pH means the solution is acidic; if the solution is acidic, that
means that there are hydronium ions in solution (H3O+). For example,
hydrochloric acid dissolves into H+ ions and Cl- ions, and the H+ ions
rreact with water like this:
H+ + H2O --> H3O+
If you want to get mathematical, pH is defined as the negative log of the concentration of hydronium ions.
Thus, if there are a lot of hydronium ions, the solution will have a low, or acidic, pH. Hope this helps^-^</span>

Here's the balanced equation for given Double displacement reaction ~

The products fored are : Lead Iodide ( PbI2 ) and Potassium Nitrate ( KNO3 )
Waves interact with matter in several ways. The interactions occur when waves pass from one medium to another. Besides bouncing back like an echo, waves may bend or spread out when they strike a new medium. These three ways that waves may interact with matter are called reflection, refraction, and diffraction.
Precipitation :)
Hope it helps