In the bond between si and br, si-br, which atom carries the partial positive charge?

This question only requires the use of relative electronegativities.

As a general rule as the metallic character of the element decreases the electronegativity of the element increases.

So, given that Si is a metalloid and Br is a non-metal element, you can expect that the electronegativity of Br is higher than the electronegativity of Si, andyou can check that in a table of electronegativities.

So, given that electronegativity is the trend to attract the electrons, in the bond Si - Br, the Br attracts the electrons with more strength than the
Si, and so Br carries a partial negative charge and Si carries a partial positive charge.

Si carries the partial positive charge, in the bond between Si and Br.

The answer is c) pyrite