Why did the mongols likely attack japan through the hakata bay in the 13th century

a. mongols thought that typhoons were less likely here than in areas bordering the sea of japan
b. mongols could launch their ships from korea, which is close to hakata bay
c. mongols hoped to surprise the japanese by attacking kyushu instead of honshu
d. mongols hoped the mountainous shoreline would be difficult for the japanese to defend