True statement about Chronic retropharyngeal abscess-a) Associated with tuberculosis of spineb) Causes psoas spasmc) Suppuration of Rouvier lymph noded) Treatment by surgery
Abscess in infants (acute retropharyngeal abscess)

Most commonly it results from retropharyngeal lymphadenitis due to an upper respiratory tract infection.
Treatment is incision and drainage. 

Abscess in adults (chronic retropharyngeal abscess)

If an adult or an older child has a retropharyngeal infection it is likely to be due to a tuberculous infection of the cervical spine (caries of cervical spine). Sometime it may be secondary to tuberculous infection of retropharyngeal lymph nodes.
Treatment includes incision and drainage of abscess along with full course of antitubercular treatment.

About option 'c'

Lateral group of retropharyngeal lymph nodes (Nodes of rouviere) may be enlarged due to TB. However, there is no suppuration, rather there is caseation.
Suppuration is seen in acute retropharyngeal abscess (not in chronic).
ad
c
ac
ab