Cell #5. Can’t compile the student’s code. Error: NameError(“name ‘t’ is not defined”)
I am getting the final o/p in my code
Which assignment is this? I can’t tell from what you’ve given us so far. In general it is the case that the grader runs your code in a different environment with different inputs. So just because things work in the notebook, that does not guarantee success from the grader. In this case, I would search your notebook carefully for any place where the code references a variable t. Can you see a reason why that code might fail in a different environment?
by mistake i changed line in a_C = tf.random.normal([1, 4, 4, 3], mean=1, stddev=4)
so it became a_C = t 
Eeeek! Glad to hear you found the issue!