Answer:
a.
Explanation:
it is not clear what your teacher discussed and wants from you here.
formally, all triangles are similar, as the description says. and the sequence of the vertexes in the "name" does not make any difference in identifying the triangle. this would be only important when identifying a specific angle (the center letter). in other words : a triangle is identified by naming its three corners in any sequence. simply because for the similarity concern you can twist and turn the triangle until it has the same orientation as the other triangle to compare.
so, again, a very strange question from your teacher. many greetings from me.
as explained, formally all 4 statements are correct.
but in order to identify one, it has to be a.
because the sequence of the corners are the same.
in QTS the side QT (the shortest of the 3 sides) is named first. and TS (the longest of the 3 sides) is named last.
in PQT we have the same sequence. PQ is the shortest side first, and QT is the longest side last.
no other answer option has the same sequence on the left and the right side.
but again, this is actually irrelevant for the similarity relation.
e.g. triangle RQS = triangle SQR, they are just twisted and turned images of the same triangle.