Eustachian tube opens due to contraction of which of the following muscles

Three muscles are related to the eustachian tube: tensor veli palatini, levator veli palatini and salpingopharyngeus. The medial fibres of the tensor veli palatini are attached to the lateral lamina of the tube and when they contract help to open the tubal lumen. These fibres have also been called dilator tubae muscle. The exact role of the levator veli palatini and the salpingopharyngeus muscles to open the tube is unceain. Dhingra 6e pg: 57