Which sequence correctly orders obscurity from lesser to greater?

Khafi, Mushkal, Mujmal and Mutashabih: Degrees of Obscurity

• Khafi → Mushkal → Mujmal → Mutashabih
• Mutashabih → Mujmal → Khafi → Mushkal
• Mushkal → Mutashabih → Khafi → Mujmal
• Mujmal → Khafi → Mutashabih → Mushkal