The answer is. :
nitrogen has 1s2 2s2 2p3 electronic configuration... it still needs 3e' to get octet structure and become stable.. hence valency=3.
I believe the correct answers from the choices listed above are options two and five. It would be metals and hydroxyl ions that are common to bases. <span>Any of a class of compounds that form hydroxyl ions (OH) when dissolved in water, and whose aqueous solutions react with acids to form salts. Hope this answers the question.</span>
It's the D. Skin hope you understand