Answer: a. Offer the product for free early on, and increase the price later
Step-by-step explanation:
When a product is said to have a network effect, what it means is that the product gets more value as more people use it. For example Whtsapp which is only such an effective means of communication because more and more people are getting it. If people did not get it, it would not be such a good medium and would be valued less.
If a company wants to price such a product, they should charge at lower rates first which would entice more people to use the product thereby giving the product more value. As the product value increases, the price can then increase to reflect this increased value.