➡ ANSWER
☑ <em><u>C</u></em><em><u>.</u></em><em><u> </u></em><em><u>3.5 105</u></em><em><u> </u></em><em><u>Hz</u></em>
Mass of CaCl₂ = 0.732 g
<h3>Further explanation</h3>
The concentration of a substance can be expressed in several quantities such as moles, percent (%) weight / volume,), molarity, molality, parts per million (ppm) or mole fraction. The concentration shows the amount of solute in a unit of the amount of solvent.

Answer:
"Wood is technically a renewable source of energy, since it is a form of biomass. All biomass is traditionally considered a renewable source of energy because it is part of the natural carbon cycle on Earth." I found this from https://www.quora.com/
Explanation:
There are a couple of ways in which you can express the concentration of a solution, and here they are: gram per liter (g/L), molarity (M), parts per million (ppm.), and percents (%).
As you can see, only M appears in your answers, which means that the correct option should be (2) 3.5 M.