read the slogan.
the window cleaner that makes glass invisible again.
which technique does the writer use to make the slogan memorable?
alliteration
a pithy slogan
word play

The answer is: A pithy slogan.

Explanation:

Let's discard the other options first...

We have: alliteration, and in this slogan it is not used this technique as this term refers to sames sounds or same consonants at the beginning of each word -this is not the case. A word play is mostly known for creating contradictions and/or redundancies -again, this is not the case. And finally a pithy phrase or slogan accordind to this context, means to give a brief but full of meaning phrase, needless to include so many words to let your audience know what you exactly mean, which here, it is the case:

What else could we add? Nothing as it is clear that if you use that product, your windows will be super clean!

this isnt an english question.

im sure you mean write *