Please answer & explain ASAP and i will leave thumbs up

Problem 2: a) If the stocks 1 and 2 have negative correlation 12 then their covariance 12 is also negative. Yes, no, uncertain. Explain. b) If stocks 1 and 2 are uncorrelated, i.e. 12=0 then their covariance is zero, Yes, no, uncertain. Explain c) If stocks 1 and 2 have variance 2=16 each, could their covariance be equal to 12=20