Fact Pattern 10-1 Lulene Makes the Best Lemon Meringue Pies in Mississippi. So

Fact Pattern 10-1
Lulene makes the best lemon meringue pies in Mississippi. So Ellen, who owns Ellen's Old Fashion Cafe, contracts with Lulene to buy 50 pies per week at the price of $5.00 per pie.
Although Lulene took a class in business law, she forgot to get her agreement with Ellen in writing. Lulene and Ellen agreed during a chat. Lulene said: "I will supply you with lemon meringue pies for however long you want them at $5.00 per pie." Ellen said: "That's great, I'll take them." Both women were pleased.
Soon Lulene had a problem. Between a hurricane in Florida and brush fires in California, the price of lemons increased by 200%. Now, instead of the $5.00 per pie price she intended to charge Ellen, she feels she must charge $7.00 per pie to make a little profit.
Lulene calls Ellen with the bad news and Ellen has a fit. She tells Lulene that's too bad, but the deal is off. Lulene says, "That's what you think!" and goes to see Amanda, her attorney.
-Refer to Fact Pattern 10-1. Under the common law, Lulene's offer:

A) is valid based on clarity
B) is valid based on communication
C) is valid based on intent
D) is invalid based on indefiniteness
E) is invalid based on illegality