What term describes the four tone marks used in Thai writing to modify the inherent tone of a syllable?

• A Sara ek, sara tho, sara tri, sara chattawa
• B Wannayuk ek, wannayuk tho, wannayuk tri, wannayuk chattawa
• C Mai ek, mai tho, mai tri, mai chattawa ✓
• D Lek ek, lek tho, lek tri, lek chattawa

The four tone marks in Thai script are mai ek ( -), mai tho ( --), mai tri ( -+) and mai chattawa ( -++), modifying the tone based on the consonant class.