Answer
See the answer below.
Work Step by Step
a) Since O and N are in period 2 and atomic radius decreases along a period, the SiO bond is shorter than the SiN one.
b) Since Si and C are in group 14 and atomic radius increases down a group, the CO bond is shorter than the SiO one.
c) Since F and Br are in group 17 and atomic radius increases down a group, the CF bond is shorter than the CBr one.
d) Since bond length decreases with bond order, the $C\equiv N$ is shorter than the C-N bond.
