Which of the following are risk factors for deep venous thrombosis? 1. Duration of surgery more than 30 minutes 2. Prior history of venous thrombosis 3. Age less than forty years 4. Obesity Select the correct answer using the codes given below: Codes:

A.   1, 2 and 3  B. 1, 2 and 4  C. 2, 3 and 4  D. 1, 3 and 4

520. The lamina propria is:

 A.  epithelial tissue 
 B.  connective tissue 
 C.  adipose tissue 
 D.  muscle tissue 

519. A 5-year-old child develops a febrile disease with cough, a blotchy rash, and cervical and axillary lymphadenopathy. Also noted is an erythematous, maculopapular rash behind the ears and along the hairline, involving the neck and, to a lesser extent, the trunk. Examination of this patient's oropharynx would likely reveal which of the following lesions?

 A.  Adherent thin, whitish patch on gingiva 
 B.  Cold sores on the lips 
 C.  Curdy white material overlying an erythematous base on the oral mucosa 
 D.  Large shallow ulcers on the oral mucosa 
 E.  Multiple small white spots on the buccal mucosa