thicker ink / a thicker ink [countable or uncountable] ?

[sb70012]

The new pens require ….. than ordinary pens do.

a)the thicker ink
b)a thicker ink (Answer Key)
c)a thickest ink
d)thicker ink

Hi,

I checked the word "ink" in the dictionaries. They say that it's [uncountable and countable]

These are my questions:
1. How should we recognize when it's (ink) countable and when uncountable?
2. Can option "d" (thicker) ink be correct as well or not?
3. To me, option "b" doesn't make sense. I mean it doesn't make sense to use article "a" for some liquid (ink).
What's your opinion?

Source: taken from school exam sheets
Thank you

 

[Pangus]

I would personally use 'd', though 'b' sounds fine, if not a little more formal.

'Ink' can be countable if we're talking about types of ink. Cambridge gives the example...

"The book is printed in three different coloured inks."

This happens with a lot of nouns that you might think of as uncountable. Off the top of my head...

"They have a wide selection of juices"
"Their soups are excellent."
"The peoples of the world came together."

 

[sb70012]

You explained "a thicker ink" very well and I thank you very much.
But would you please be nice enough to clarify "thicker ink" too?
Now I understood that "a thicker ink" talks about types of ink. But what about "thicker ink"?
I mean if option "b" is about types of ink, then what's option "d" about?

 

[MikeNewYork]

You explained "a thicker ink" very well and I thank you very much.
But would you please be nice enough to clarify "thicker ink" too?
Now I understood that "a thicker ink" talks about types of ink. But what about "thicker ink"?
I mean if option "b" is about types of ink, then what's option "d" about?

It just refers to ink that is thicker than standard ink. This is the same construction as "colder water".

 

[probus]

Ink, like water, can be countable or non-countable depending on context.

More water may be needed.
The best prawns come from colder waters.

More ink tends to produce darker colours.
Some inks are easier to make than others.