python programming

Moving to another question will save this response. Question 13 Which of the following is an invalid variable? a. O b. my_string_1 c. foo O d. 1st_string A Moving to another question will save this response. Moving to another question will save this response. Question 14 Which of the following Python statement is invalid? a. a1 = "Grade" b._str_ = "Hello World" O c. Samount = 5000.00 d. _a=1 Moving to another question will save this response. Moving to another question will save this response. Question 15 What is the output of the following Python statement? str="hello" print (str[:2]) O a. hel b. hello O c. Lo d. he Moving to another question will save this response