Teachers usually blame a student's learning problems on

Teachers most commonly attribute a student's learning problems to a lack of motivation.

Blaming low drive locates the cause in the learner's willingness rather than in teaching or ability.

Lack of intelligence is a less frequent charge and wrongly treats ability as fixed and the sole cause.

A casual parental attitude shifts blame to the home and is not the usual first explanation teachers reach for.

The none option fails because motivation is indeed the habitual explanation teachers offer.

Attribution theory studies exactly such causal explanations for success and failure in learning.