I buy a packet of captain crunch cereal it normally has 12oz but has 25% extra free how many ounces is in a packet

The answer for #3 is c but i don't know why

Which set of characteristics best describes igneous rock? a) largest type of rock, made of organic matter, hardest type of rock b) least abundant type of rock, made of other rocks, made mostly of minerals c) found on all continents, contains wavy bands of stripes, contains fossils d) most abundant type in earth's crust, made of magma/lava, contains no fossils

Which atom or ion is the largest? a. k b. k+ c. ca d. ca2+ e. li