'Velar' is the sound formed by:

Correct option is D

A velar sound is produced when the back of the tongue contacts the soft palate (velum). Examples include the sounds /k/, /g/, and /ŋ/ as in "cat," "go," and "sing."
Information Booster:
1. Articulators involved: Back of the tongue and velum (soft palate).
2. Examples: /k/, /g/, and /ŋ/ are common velar sounds in English.
3. Voicing distinction: /k/ is voiceless, while /g/ and /ŋ/ are voiced velars.
4. Common usage: Found in many languages, not just English.
5. Phonetics context: Velar sounds are classified as stop consonants or nasal sounds.
Additional Knowledge:
(A) The front of the tongue and the hard palate: Refers to palatal sounds like /ʃ/ or /ʒ/. These are not velar sounds. (B) The lower lip and the upper teeth: Refers to labiodental sounds like /f/ and /v/. (C) The blade of the tongue and teeth ridge: Refers to alveolar sounds like /t/, /d/, or /s/.