What do the red-colored blocks indicate? A. non-metals B. alkali metals C alkaline earth metals D. noble gas

## Step 1: Identify the highlighted elements<br />### The image description indicates that the red-colored blocks highlight specific elements on the periodic table. These elements include Hydrogen (H), Carbon (C), Nitrogen (N), Oxygen (O), Fluorine (F), Phosphorus (P), Sulfur (S), Chlorine (Cl), Selenium (Se), Bromine (Br), Iodine (I), Astatine (At), Helium (He), Neon (Ne), Argon (Ar), Krypton (Kr), Xenon (Xe), and Radon (Rn).<br /><br />## Step 2: Determine the category of these elements<br />### The highlighted elements are primarily located on the upper right side of the periodic table, which is characteristic of non-metals. Non-metals include elements such as hydrogen, carbon, nitrogen, oxygen, fluorine, phosphorus, sulfur, chlorine, selenium, bromine, iodine, and astatine. Additionally, the noble gases (helium, neon, argon, krypton, xenon, and radon) are also considered a subset of non-metals.<br /><br />## Step 3: Match the highlighted elements to the given options<br />### The question provides four options: A. non-metals, B. alkali metals, C. alkaline earth metals, D. noble gases. Since the highlighted elements are non-metals, including some noble gases, the correct option that encompasses all the highlighted elements is "non-metals."