According to -- as stated by.
Because of -- on account of; by reason of.
Inspite of -- even though.
Though -- despite the fact that; although. According to me, you should read English newspapers daily.
Superlative form of adjective ‘popular’ is . . . . .
Using "a" and "the" depends on how specific or general we want to be when talking about something.
"A" is used for a non-specific or generic reference. For example, "I travel by a bus" implies any bus in general.
"The" is used when referring to a specific instance or when both the speaker and the listener know which particular bus is being discussed. For instance, "I travel by the bus" could imply a specific bus service or route that is commonly known between the speaker and the listener.
In the above question "Why do you travel by a bus" is more appropriate because it is a general talk rather than any specific bus service or route.
Therefore, option A is the correct answer here.
You speak so . . . . . that I can’t understand properly.