Read the text and determine if the sentence is true (see options at the end):

Political leaders pledged that construction of the so-called Freedom Tower -- which will rise 1,776 feet into the air and be the world's tallest building -- will be finished on schedule by the end of 2008.

Sentence: Political leaders have pledged nothing.
pick from the following.
 a). Yes;
 b). It's impossible to say;
 c). No;
c).