English is thought to be ... than math. Jupiter is ... planet in the solar system

6.English is thought to be......than math 
a.harder       b.the more hard         c.hardest        d.the hardest
7. Jupiter is......planet in the solar system
a the biggest    b.the bigger     c.bigger     d.biggest
8.my house is.....hers
a.cheap than      b.cheaper       c.more cheap than       d.cheaper than
9.her office is.....away than mine
a.father       b.more far          c.farther         d.farer
10.Tom is .........than david
a.handsome        b.the more handsome          c.more handsome         d.the most handsome
11.he did the test.......I did
a,as bad as          b. badder than         c.more badly than           d.worse than
12.A boat is........than a plane
a.slower          b.slowest        c.more slow           d.more slower
13.my new sofa is......than the old one
a.more comfortable        b.comfortably         c.more comfortabler         d.comfortable